Clearomiser, atomiser, Pyrex and drip tip: what does each do?

The clearomiser is the upper part of an e-cigarette: the transparent tank containing the e-liquid, the coil that heats it and the mouthpiece through which you inhale. The atomiser refers to the entire heating system, the pyrex is the tank's glass wall, and the drip tip is the removable mouthpiece.

These four terms refer to different things, and confusion can prove costly when ordering a spare part. This article clarifies the terminology, explains the purpose of each component, and specifies what needs replacing when a part breaks or vaping performance deteriorates.

Key points to remember

• Clearomiser: the complete tank, coil and mouthpiece assembly that screws onto the battery. This is the part purchased as a complete unit.
• Atomiser: the generic term for any heating system. A clearomiser is an atomiser with a transparent tank.
• Pyrex: the glass wall of the tank. It can be replaced on its own when it breaks.
• Drip tip: the removable mouthpiece. The two main diameters are 510 and 810.
• The most common thread between a clearomiser and battery is the 510, but coil compatibility depends on the model.
• A pre-filled tank cannot exceed 2 ml in France, under the order of 19 May 2016^[1].

The clearomiser, the central component

A clearomiser screws onto the battery and combines three functions: holding the liquid, heating it and delivering it to the mouth. The word comes from clear, because the wall is transparent and lets you see the remaining level. This is its historical difference from older opaque cartomisers.

What you buy under this name is the assembled unit: the metal body, pyrex, coil base, airflow ring and drip tip. The coil is a consumable and is sold separately.

Choosing a clearomiser is based on three verifiable technical criteria: capacity in millilitres, the type of draw it provides, and the coil range it accepts. The last point is the most important: it determines running costs and the long-term availability of parts.

View clearomisers

Atomiser, the generic term

Atomiser refers to anything that turns a liquid into an aerosol. It is the category, not the product. A clearomiser is an atomiser; a dripper, which has no tank and is fed drop by drop, is another; and a rebuildable atomiser, in which you fit your own resistance wire and cotton, is a third.

In everyday shop use, atomiser is often used as a synonym for clearomiser. This is not wrong; it is simply broader. The distinction matters mainly when looking for a part: a clearomiser pyrex will not fit a dripper, which does not have one.

Pyrex, the part that breaks

Pyrex is the glass tube forming the wall of the tank. It is the most fragile component of the assembly: a drop onto tiled flooring is enough. The good news is that it can be replaced on its own, without changing the clearomiser.

There are two precautions when ordering. First, pyrex is model-specific: Zeus pyrex will not fit a Zenith. Second, the same clearomiser often comes in several capacities, with straight glass and domed glass, known as bulb glass, which increases capacity without changing the diameter. Check the capacity stated on the product page before confirming your order.

A worn O-ring causes the same symptoms as cracked pyrex: seepage at the base and liquid in the battery. Replacement pyrex is generally supplied with its seals.

View replacement pyrex

The drip tip and the two diameters to know

The drip tip is the mouthpiece through which you inhale. On most clearomisers it is removable, allowing you to replace it, clean it separately or change its shape.

Two standards share the market:

Adaptors are available for fitting a 510 mouthpiece to an 810 base. Do not confuse this 510 with the 510 thread that connects the clearomiser to the battery: the same number, but two different parts.

Some models use a proprietary, non-interchangeable mouthpiece. Others, such as filter pods, accept cotton or paper filters that need changing regularly.

View drip tips and mouthpieces

The coil, the only truly consumable part

The coil is the small cylinder fitted into the base of the clearomiser. It contains a heating wire and cotton saturated with liquid. It is the part that wears out, and it is specific to each clearomiser range.

Its value, expressed in ohms, determines the type of vaping: above 1 ohm for a tight draw at low power, below that for an airy draw at high power. Details can be found in which value to choose for my coil, and the corresponding setting in e-cigarette power.

For its lifespan and signs of wear, see how long a coil lasts and signs of a faulty coil.

View coils

The draw and the ring that adjusts it

The airflow ring is located at the bottom of the clearomiser. Turning it opens or closes the slots that let air in.

• Tight draw, known as indirect: little air passes through, creating a sensation similar to a cigarette. The vapour is held in the mouth before inhaling.
• Airy draw, known as direct: air flows freely, allowing you to inhale directly into the lungs, with much more vapour.

New ex-smokers usually prefer a tight draw because the action feels familiar. The choice of clearomiser should follow: a model designed for an airy draw remains unpleasant, even with the ring closed fully.

Filling without making a mess

Most recent clearomisers are filled from the top, while older models are filled from the bottom. In both cases, the rule is the same: never pour liquid into the central chimney, the tube through which air passes. The liquid would flow directly into the battery.

After fitting a new coil, allow the cotton to soak for several minutes before the first puff; otherwise, it will burn. The full method is described in how to fill an e-cigarette.

Leaks and their causes

A leak almost always results from one of these six causes:

• a coil that is not screwed in properly or is cross-threaded;
• a coil that is too worn;
• a split, distorted or incorrectly refitted O-ring after cleaning;
• cracked pyrex, sometimes split without the crack being visible;
• a liquid that is too thin for the coil used, typically a liquid high in propylene glycol used with a large coil;
• overfilling, which leaves no air pocket to maintain negative pressure.

If the problem persists after these checks, the article on faults and error messages lists rarer cases.

Cleaning and maintaining the assembly

A clearomiser can be fully dismantled and washed, except for the coil. The metal parts and pyrex can be rinsed in lukewarm water, dried and reassembled once dry. The coil cannot be usefully cleaned: its cotton is saturated, so it must be replaced completely every 3 weeks at most.

Cleaning when changing the coil or flavour is sufficient in most cases. The procedure is detailed in how to clean your e-cigarette.

Frequently asked questions about clearomisers

Sources

^[1] Ministry of Social Affairs and Health. Order of 19 May 2016 concerning nicotine-containing vaping products. Official Journal of the French Republic No. 0116 of 20 May 2016; Articles 1 to 3. In force on 5 October 2026.

^[2] French Agency for Food, Environmental and Occupational Health & Safety. Vaping products. Anses, 4 February 2026. Nearly 200,000 products declared since 2016 and more than 2,200 substances listed as ingredients.

^[3] Public Health Code, Article L3513-5-1. Légifrance, version in force since 26 February 2025.

^[4] Public Health Code, Articles L3513-1 to L3513-6. Légifrance, version in force on 5 October 2026. Definition of vaping products and prohibition of sales to minors.

^[5] Directorate for Legal and Administrative Information. Ban on vaping (e-cigarette). Service-Public.fr, page checked on 20 July 2026.

This article is for information only and does not replace advice from a healthcare professional. Vaping products are prohibited for minors and are not intended for non-smokers. Nicotine is highly addictive. For support with quitting smoking: Tabac info service, 39 89.