Innokin Cool Fire 4 IV Vape Starter Kit

Overview

The Innokin Cool Fire 4 IV Vape Starter Kit by Innokin across 4 flavours at 0mg. Free UK delivery over £20, same-day dispatch on weekday orders before 4pm.

Overview of the Innokin Cool Fire 4 IV Vape Starter Kit

The Innokin Cool Fire 4 IV Vape Starter Kit is a refillable, rechargeable vaping kit built around a compact box-style device with an integrated battery and a sub-ohm tank that threads onto the top. It sits in the middle ground between a basic pod kit and a full enthusiast setup. You get adjustable power, a tank that takes replaceable coil heads and a body small enough for a jacket pocket, but you are not asked to learn what a removable 18650 cell is, wrap your own coils or work through Ohm's law before your first puff.

Innokin is an established hardware manufacturer that has been making vaping products for well over a decade, and the Cool Fire series has been one of its recurring product lines. The idea behind the range is simple. Take a proven power platform, pair it with a tank that can be refilled from a standard 10ml bottle, and sell the whole thing as one boxed kit so that a new or switching vaper does not have to match components from different brands. The Cool Fire 4 IV follows that formula and is aimed at adult smokers moving away from cigarettes, as well as existing vapers who want a dependable second device for the office, the car or travel.

Because this is a hardware product and not a pre-filled device, several of the things people ask us most often, such as puff counts, flavour and nicotine strength, depend partly on what you put inside it. Where we quote numbers in this guide we try to make clear whether they reflect the platform's published headline figures or are our own estimates based on how this class of device behaves in normal use. Always treat the specification table on the product page as the final word on exact figures for the unit you are buying.

A quick summary of what you are looking at:

• Format: refillable starter kit with an all-in-one style mod and a threaded sub-ohm tank.
• Power: adjustable output on a built-in rechargeable battery, charged over USB.
• Tank: small-capacity sub-ohm tank with replaceable coil heads, filled from the top or side depending on the tank design.
• E-liquid: not included, so you will need a bottle of your own choosing. Shortfill bottles with a nicotine shot are a separate route and are explained further down.
• Age restriction: sold to adults aged 18 and over only.

The kit appears in five variants in our catalogue. The variants are different options of the same product family. The core hardware, the way it is used and the advice in this guide apply across all of them, so choose the version that matches the look you prefer.

Performance and Vapour Delivery

Disposable vapes are often marketed on a puff count, which is a tidy number printed on the side of the pack. Refillable kits do not work that way. A kit like the Cool Fire 4 IV has no fixed puff count, because the number of draws you get depends on the e-liquid you put in, the coil you fit, the power you set and how you draw. What can be said is how much vapour the device is built to deliver and how long a tank tends to last in real use.

The Cool Fire 4 IV is a sub-ohm style kit. Sub-ohm means the coil in the tank has a resistance below one ohm, which lets the battery push more power through it and produce a larger, warmer cloud than a restricted-lung pod device. In practice that translates to a looser, airier draw. You inhale slowly and directly into your lungs, much the way you would draw on a large vape pen, instead of the tight, cigarette-like mouth-to-lung draw you get on most pod kits. If you are used to a tight draw, expect a short adjustment period.

As a rough guide to how long a tank lasts, a small sub-ohm tank filled with around 2ml of liquid will typically be good for somewhere in the range of 100 to 250 draws, depending on wattage and how long each draw is. That is our estimate rather than a lab figure, and it will shift in either direction. At lower power settings with a tight air-flow ring and short draws you will be at the upper end. Run the device hot with the air-flow fully open and you will empty the tank noticeably faster. Many people find they refill once or twice over a working day, which is why a larger bottle at home is more economical than buying small pre-filled items.

There are three things that control performance more than any other:

• Power setting: higher output heats the coil harder, gives more vapour and a warmer draw, and uses liquid and battery faster. Staying inside the range printed on the coil head is what keeps flavour clean.
• Air-flow: opening the air-flow ring cools and loosens the draw; closing it makes the draw tighter and the flavour more concentrated.
• E-liquid ratio: a higher-VG liquid makes bigger, denser vapour but is thicker and can be slower to soak into the cotton; a more balanced 50/50 liquid is thinner and tends to give a sharper throat feel and crisper flavour.

Throat hit deserves a mention because it surprises many first-time sub-ohm users. At the same nicotine strength, a sub-ohm device delivers a lot more liquid per draw than a pod system, so more nicotine reaches you per puff. That is the main reason we recommend lower strengths for this style of kit, which we cover in the nicotine section below.

Flavour Profile and What Affects It

A hardware kit has no flavour of its own, so the question to ask is how faithfully the Cool Fire 4 IV reproduces the flavour of whatever e-liquid you choose. In a sub-ohm tank with a coil head that is correctly primed, the answer is reasonably well. The coil is wide enough to heat a lot of liquid at once, the draw is airy and the tank is small, which means the liquid does not sit in the chamber for long. That combination favours clean, recognisable flavours and avoids the stale-tank taste that can creep in with large reservoirs.

Flavour character shifts with power. At lower settings the vapour is cooler and the top notes of a fruit or menthol liquid come through more clearly. At higher settings the vapour warms up and the sweeter, heavier notes such as custard, dessert, caramel and tobacco-style blends become fuller. If a liquid tastes thin or slightly harsh, a small change in output of two or three watts is often enough to bring it into balance. The recommended range printed on the coil head is a sensible place to start, and most people settle just above the lower end of it.

Which liquids suit this kit? Here is a practical guide:

• Fruit and ice blends: work well at moderate output. The wide airflow keeps menthol and cooling agents from feeling overpowering.
• Dessert and bakery flavours: these are heavier liquids with more sweeteners and can build up on the coil faster. Use a slightly higher power and expect to replace the coil head sooner.
• Tobacco and nutty blends: suit cooler, lower-power settings, where the dryness and depth of the flavour is preserved.
• Sweet-heavy liquids: can darken a coil quickly. If a liquid starts to taste burnt, change the coil head before blaming the liquid.

New coil heads need a short break-in. Fill the tank, let the liquid soak into the cotton for at least five to ten minutes without firing, and take a few gentle draws at low power before moving up to your normal setting. A dry or under-primed coil is the most common cause of a flat or scorched first tank, and it has nothing to do with the e-liquid itself.

Finally, remember that nicotine strength changes how flavour feels. A higher-strength liquid brings more throat hit that can mask delicate notes, while a lower-strength liquid lets the flavour carry the experience. If you are trying a new flavour, it is worth starting with a lower-nicotine bottle at a sensible power setting and then adjusting.

Design and Build Quality

The Cool Fire 4 IV uses a rounded, box-style body that is meant to sit comfortably in the hand and slip easily into a pocket. The tank sits flush on top so the two parts read as a single unit, which is a design choice that makes it easier to carry and less likely to snag on fabric than a taller mod and tank stack. Innokin's finishing on this series has traditionally been tidy, with consistent panel gaps, a matte or satin surface that resists fingerprints better than gloss and a fire button that is large enough to find without looking.

Controls are kept simple. A single fire button sits on the front or side, with small adjustment buttons for changing the power level and a compact display that shows the figures you need: output, battery level and, where applicable, the coil reading. Pressing the fire button five times in quick succession is the near-universal convention for switching a box mod on and off, and it is how most Innokin devices handle it. This also acts as a child-lock of sorts, because a device that is switched off will not fire when it is knocked around in a bag.

The body is built from a zinc alloy and plastic composite, a material combination used across the mid-range because it balances weight, durability and cost. It feels solid rather than heavy, and it tolerates the everyday bumps that come with a pocket device. It is not waterproof or drop-proof, so we would not recommend treating it as a rugged tool. A silicone sleeve or a small case is a sensible and inexpensive precaution if you carry it with keys or coins.

Points to check when your kit arrives:

• The tank should thread onto the 510 connector smoothly with no cross-threading. If it stops after half a turn, back it off and try again rather than forcing it.
• The battery door or charging port cover, if fitted, should close fully.
• The air-flow ring on the tank should rotate cleanly with a light resistance.
• The tank glass or plastic window should be free of cracks, and the drip tip should sit firmly in its seat.

One honest point about the design: this is an integrated-battery device. You cannot swap in a fresh cell when the battery runs low, so a full charge cycle is the only way back to power. For many people that is a fair trade for the simplicity and the slimmer body, but anyone who vapes heavily through the day should keep that in mind.

Battery Life and Charging

The Cool Fire 4 IV generation is built around a non-removable lithium-ion battery. The platform's published capacity is in the region of a couple of thousand milliamp-hours, which is a typical figure for a pocket-sized box device of this size. Check the specification table on this page for the exact capacity of the version you are buying, because Innokin has released the Cool Fire name in several size and power configurations over the years.

How long does that last? Battery life on a sub-ohm kit is more variable than most people expect. As a working estimate, a full charge generally covers a light to moderate day of use: perhaps half a day to a full day for someone who takes occasional draws, and noticeably less for someone who chain-vapes at higher wattage. As a rule of thumb, the higher you run the power, the faster the battery drains. Dropping the output by a few watts can add a surprising amount of runtime for a small change in vapour.

Charging is done over a standard USB cable connected to the port on the device. A full charge from empty typically takes in the region of two hours on a standard one-amp adapter. Some practical tips:

• Use a reputable charger: a phone-style 5V USB adapter of one to two amps is ideal. Avoid cheap unbranded adapters with no safety markings.
• Charge on a hard, flat surface: never on a bed, sofa or in a bag, and keep it away from direct sunlight and radiators.
• Do not leave it charging overnight on a regular basis: modern devices have charge protection, but unattended charging of any lithium battery product is a risk that is easy to avoid.
• Unplug when full: topping up in short bursts is fine, but a full battery does not need to stay on the lead.
• Keep the contacts clean: a dab of tank leakage on the 510 connector can interfere with firing and drain the battery faster.

When the battery finally ages, which usually takes at least a year or more of regular use, you will notice shorter runtimes and slower charging. Because the cell is built in, it cannot be replaced by the user, and the sensible path is to retire the device responsibly. Lithium batteries must not go in general household waste or recycling bins. In the UK, vaping devices count as waste electrical equipment, and you can take them to a household waste recycling centre or to a retailer or drop-off point that offers vape and battery recycling. Remove the tank and any e-liquid first, and keep the device away from heat and moisture until it is handed over.

Coil and Tank Technology

The tank is the part of a kit that decides how it performs, so it is worth understanding what is going on inside. The Cool Fire 4 IV uses a compact sub-ohm tank with replaceable coil heads. Each coil head is a small metal cartridge containing a heating element, usually a wire coil or a mesh sheet, wrapped or backed with organic cotton. E-liquid wicks from the tank into the cotton through small holes in the side of the coil head, and when you press the fire button the battery heats the element and turns that liquid into vapour.

Resistance is expressed in ohms. Sub-ohm heads typically fall between roughly 0.3 and 1.0 ohm depending on the model, and the lower the number, the more power the head is designed to take. A lower-resistance head produces more vapour and a warmer draw; a slightly higher-resistance head produces a tighter draw and uses less liquid. The correct power range is printed on the side of every coil head, and staying inside it matters. Running a coil above its stated range is the quickest way to burn the cotton, and running it far below the range tends to give weak, lukewarm vapour.

Tank capacity is a legal matter in the UK. Refillable tanks sold in the UK are limited to a maximum capacity of 2ml, and nicotine e-liquid bottles are limited to 10ml for liquids that contain nicotine. Many tanks are sold in other markets with a larger capacity, and UK versions achieve compliance with a smaller glass section or a restrictor in the tank. This is why a UK-supplied kit fills up quickly and why carrying a bottle is part of daily use.

Key tank design points:

• Fill method: most Innokin kits of this style use a top-fill or side-slide fill port. Fill by dripping liquid slowly down the inside wall and avoid covering the central air tube.
• Air-flow control: a rotating ring lets you open or restrict the air channels to tune the draw.
• Leak resistance: sub-ohm tanks can leak if they are overfilled, left lying on their side or if the coil is not seated properly. Fill to just under the maximum line and keep the device upright.
• Maintenance: rinse the tank under warm water when you change a coil, dry it fully, and replace the O-rings if they stretch or crack.

Coil life is not fixed. A head will often last one to three weeks of regular use, but sweet or dark liquids shorten that and cleaner flavours extend it. The sign to change is when the flavour turns dull or toasty even though the tank is full and primed.

Nicotine Strength Guidance

Choosing a nicotine strength is the single decision that most affects whether a switch from cigarettes works. In the UK, e-liquid containing nicotine is capped at 20mg/ml (2%) for bottles and the same ceiling applied to disposables when they were still sold. You will never be able to legally buy a stronger refill than that from a UK retailer. The cap has an effect on how you should pair a liquid with the Cool Fire 4 IV, because the answer depends on whether the liquid is a freebase or a nicotine salt.

Because this kit is a sub-ohm device with a loose, direct-to-lung draw, it delivers a lot of liquid per puff. Lower-strength freebase liquid is the usual match. As a starting point:

• Heavy smokers (20 or more cigarettes a day): try 6mg/ml freebase, or move up to 12mg/ml if you still feel cravings after a few days. Many people find sub-ohm vaping less satisfying at 12mg because the throat hit becomes harsh at higher power.
• Moderate smokers (10 to 20 a day): 3mg/ml to 6mg/ml is a sensible range to try first.
• Light smokers or social smokers: 3mg/ml is usually enough, and some start at 0mg to 1.5mg once they are comfortable with the habit.
• Ex-smokers using vaping to stay off cigarettes: 0mg to 3mg/ml is common and gives you the hand-to-mouth routine without much nicotine.

Nicotine salt liquids at 10mg/ml and 20mg/ml are formulated for low-power devices and mouth-to-lung draws. They are smoother at high strength, but they are not an ideal pairing for a sub-ohm coil at 30 or 40 watts, because the nicotine delivered per puff becomes much higher. If you want to use nic salts on this kit, run it at the bottom of the power range, choose a higher-resistance coil head if one is available and take shorter, gentler draws. Otherwise a pod kit is a better match for salt strengths.

Shortfill bottles with separate nicotine shots are another option. A 50ml bottle sold with 0mg nicotine has room for a 10ml shot, which brings it to roughly 3mg/ml. This route is cheaper per millilitre and suits people who vape a lot. Always follow the mixing instructions on the shot and bottle, and keep the shot and the finished liquid labelled and out of reach of children.

Nicotine is addictive and this kit is intended for adult smokers and existing vapers. If you have never smoked or vaped, you do not need to start. If you have a medical condition, are pregnant, or take regular medication, talk to your GP or a stop-smoking service before changing your nicotine intake.

Who the Cool Fire 4 IV Is For

No single device suits every vaper. The Cool Fire 4 IV is a good match for a reasonably specific group of people, and an honest recommendation includes the ones who should look elsewhere.

Who should consider it:

• Smokers making their first serious attempt at switching: the kit gives enough vapour and throat hit to feel like a replacement for a cigarette, with controls simple enough to learn in an afternoon.
• Disposable users looking for a lower running cost: since the sale of single-use disposable vapes was banned in the UK from June 2025, refillable and rechargeable devices are the practical route. A kit pays for itself quickly compared with buying one-off devices every few days.
• Ex-pod users who want more vapour: if a closed pod system has started to feel restrictive, a sub-ohm kit gives a bigger, warmer draw without going to a full enthusiast setup.
• People who want a spare device: a second kit that lives in the car, desk drawer or travel bag saves carrying your main device everywhere.

Who might prefer something else:

• Anyone who wants a very small, discreet device: a pod kit is slimmer and quieter and gives a tight draw closer to a cigarette.
• Heavy daily users who want long runtime: an integrated battery limits you to one charge, so a kit with a removable cell or a larger-capacity battery gives more flexibility.
• People who want to use high-strength nic salts: a dedicated pod system is a closer match.
• Enthusiasts who want to rebuild their own coils: this kit is built around replacement heads, not rebuildable decks.

A final point on who this is not for: anyone under 18. Vaping products are legally restricted to adults, and so is the purchase of a kit like this. We may ask for age verification at checkout or on delivery, and the courier may ask for ID.

If you are not sure whether a sub-ohm kit or a pod kit is right, think about what you are replacing. A smoker who wants the closest feel to a cigarette usually does well with a mouth-to-lung pod kit. A smoker who found cigarettes harsh and wants a warmer, fuller inhale often prefers a sub-ohm style device like this one. Neither is a better or worse choice, they just suit different habits.

How to Use the Kit: Setup, Filling and First Puffs

Getting the Cool Fire 4 IV running takes about ten minutes, most of which is waiting for the coil to soak. Follow the order below and you will avoid the usual first-day problems.

• Step 1, charge: plug the device into a USB adapter with the supplied cable and let it reach a full charge before first use. A full first charge helps set a sensible battery baseline.
• Step 2, prepare the tank: unscrew the base, remove any protective plastic from the coil head and any shipping film on the tank, and rinse the tank sections in warm water to clear dust from manufacturing. Dry them completely.
• Step 3, fit the coil: screw the coil head firmly into the base of the tank until it is snug. A loose coil is a common source of leaks.
• Step 4, fill: with the tank upside down or open at the top fill port, add e-liquid slowly down the side wall. Stop just below the maximum line and avoid the central air tube. Close the tank.
• Step 5, prime: stand the tank upright for at least five to ten minutes so the liquid soaks into the cotton. This is the step that most people skip and then wonder why the first draws taste burnt.
• Step 6, attach and switch on: screw the tank onto the 510 connector, then click the fire button five times to switch on.
• Step 7, set the power: start at the low end of the range printed on the coil head and take a few slow draws. Raise it in small steps until the flavour and warmth are right.

Draw technique matters on this style of device. Take a slow, steady draw of three to four seconds and breathe the vapour into your lungs, not just your mouth. A short sharp puff will not heat the coil evenly and gives a thin, lukewarm hit. If the device has an automatic cut-off, which most do after around ten seconds, avoid holding the button longer than that.

Everyday handling tips:

• Keep the device upright when it is not in use, particularly in a bag.
• Switch it off with five clicks when carrying it, so it cannot fire by accident.
• Top up the tank before it runs fully dry. Firing a dry coil is the fastest way to ruin it.
• Wipe the connector and the outside of the tank when you refill, so liquid does not creep into the electronics.
• Store spare e-liquid upright, away from sunlight, and out of reach of children and pets.

When you eventually change the coil head, empty the tank, unscrew the base, swap the head, prime the new one and begin again at a lower power until it has settled in.

Troubleshooting Common Problems

Most problems with a refillable kit come from a handful of causes, and almost all of them have simple fixes. Here is a checklist for the issues we see most often.

• Burnt or harsh taste: usually a dry or old coil. Check the liquid level, give the coil a few more minutes to soak, lower the power and take shorter draws. If the burnt taste persists after a refill, the coil head has reached the end of its life and should be replaced.
• Weak or muted flavour: often a worn coil, a low battery or the wrong power for the liquid. Try a new coil, charge the device and nudge the power up by a watt or two.
• Gurgling or spitting: the coil is flooded. This tends to happen with thick, high-VG liquid or an overfilled tank. Open the air-flow, blow gently through the drip tip with the device switched off and wipe away excess.
• Leaking from the base or air-flow holes: check that the coil is screwed in tightly, that the tank is not filled past the maximum line, and that the O-rings are present and undamaged. A leaking tank should be cleaned and re-seated before it is used.
• Device will not fire: make sure it is switched on with five clicks, that the battery is charged, and that the tank is threaded correctly onto the 510 connector. Wipe the connector and the tank's centre pin to remove residue.
• Check Atomizer or No Atomizer message: the device cannot detect a coil. Unscrew the tank, make sure the coil is seated, clean the contacts and try again.
• Short circuit or Low Resistance message: the coil may be shorted or the tank not seated correctly. Remove the tank, check for debris on the connector and swap in a new head if it persists.
• Battery drains quickly: high power settings and a degraded cell are the usual reasons. Lower the output and check that the device is not firing accidentally in a bag.
• Device warm to the touch while charging: mild warmth is normal, but if it becomes hot, unplug it, let it cool in a safe place and do not use it again until you have contacted the retailer or manufacturer.

A basic safety note: if a lithium battery device swells, smells of burning, emits smoke or becomes unusually hot, stop using it immediately, move it away from flammable materials and do not attempt to charge it again. Never use a damaged battery device.

If you have worked through the list and the kit still does not behave, get in touch with your order number and a short description of the fault. A clear photo or short video of any error message helps us help you faster.

Value for Money and Running Costs

The sticker price of a starter kit is only part of the picture. A better way to judge value is to look at what it costs to run over a few months, and how that compares with the alternatives.

With a refillable kit, your ongoing costs are e-liquid, replacement coil heads and the electricity to charge it, which is negligible. A typical user of a sub-ohm style kit may get through anywhere between 3ml and 6ml of liquid a day, with considerable variation either side. At that rate a 50ml shortfill bottle lasts roughly one to two weeks. A coil head usually lasts one to three weeks and costs a small fraction of the kit price. Over a month, a regular user of a kit like this can expect to spend noticeably less than a regular user of single-use disposables, and much less than a pack-a-day cigarette habit.

Here is how the costs break down in practice:

• Upfront: the kit itself, usually less than the cost of a few cartons of cigarettes.
• E-liquid: buying 50ml shortfill bottles with nicotine shots is the cheapest route per millilitre. Ready-mixed 10ml bottles are simpler but cost more over time.
• Coils: packs of replacement heads are cheaper than buying single heads, and buying a pack with a few spares avoids running out at an awkward moment.
• Replacement: since the battery is integrated, expect to replace the entire device after a year or two of daily use rather than just a cell.

The environmental angle is part of value too. Single-use disposable vapes, now banned from sale in the UK, produce a high volume of electrical and battery waste. A refillable kit produces less waste per month of use, and the packaging from e-liquid bottles and coil heads is easier to recycle. When the device reaches the end of its life, take it to a household waste recycling centre, a WEEE collection point or a retailer offering take-back. Do not put it in the general bin or kerbside recycling, because lithium batteries can start fires in collection vehicles.

Is it good value? For a smoker or ex-disposable user who wants a reliable everyday kit and is happy to refill a small tank, yes. For someone who wants the lowest possible maintenance or maximum runtime, a different style of device may offer better value for their situation. The price becomes much harder to argue with when you count how long one kit lasts.

How It Compares with Alternatives

Fair comparisons are only possible if you are clear about what you want from a device. Here is how the Cool Fire 4 IV compares with the main alternatives we are asked about, with the strengths and weaknesses of each stated plainly.

Versus pod kits (for example, Vaporesso or SMOK pod systems): modern pod kits are smaller, lighter and tend to offer a tight mouth-to-lung draw that feels closer to a cigarette. They are also usually simpler, with a single button and a closed pod. The Cool Fire 4 IV gives a bigger, airier draw and adjustable power, but it is larger and takes more setup. If you want to hold something as small as a lighter, a pod kit wins. If you want adjustable output and replaceable coil heads, the Cool Fire 4 IV fits better.

Versus other starter kits in the same price bracket (such as Aspire, Geekvape or Vaporesso box-style kits): these brands all offer comparable sub-ohm starter kits with integrated or removable batteries. Some newer kits use more recent chipsets and larger batteries, and a few offer fast charging over USB-C. The Cool Fire 4 IV is a long-running design and, in some respects, shows its age: the platform is older than the latest generation, and its charging connector and feature set reflect that. Its strengths are simple controls, familiar Innokin build quality and widely available coil heads.

Versus advanced mod and tank setups: a separate mod and rebuildable or high-power tank will outperform this kit on power, battery life and customisation. They also cost more, require more knowledge and carry more risk if used incorrectly. The Cool Fire 4 IV is a gentler step, not a competitor to enthusiast hardware.

Versus disposable vapes: disposables are no longer sold in the UK, but many people still compare them. A refillable kit costs more upfront but much less to run, produces less waste and gives you freedom to choose your own liquid and strength. The trade-off is the small routine of charging and refilling.

A quick comparison at a glance:

• Ease of use: pod kits are simplest; the Cool Fire 4 IV is a small step up; mod-and-tank setups are the most demanding.
• Vapour and flavour: sub-ohm kits like this deliver more than most pod kits, but less than high-power enthusiast setups.
• Portability: pod kits are smallest, this kit is moderate, mod setups are largest.
• Running cost: all refillable options beat single-use devices over time.

The honest summary is that the Cool Fire 4 IV is a dependable, established choice for people who want adjustable power in a compact all-in-one body, without chasing the newest specifications. If you want the latest charging or chipset features, compare it with the current range before you buy.