ONEWING GROUP LIMITED › RELX HERC 12000 › What Does Airflow Mean on a Vape? MTL vs RDL Explained Simply

What Does Airflow Mean on a Vape? MTL vs RDL Explained Simply

By ONEWING GROUP LIMITED · Updated 2026 · Reading time: 6 min

Ask ten customers what airflow means on a vape and eight will shrug. Yet airflow is the single biggest reason two devices with identical puff counts can feel completely different in the hand. Here is the plain-English version, written for shop-floor conversations between retailers and adult customers.

Airflow in one sentence

Airflow is the amount of air that mixes with the vapour on its way from the coil to your mouth. More air means a looser, cooler, cloudier draw. Less air means a tighter, warmer draw that feels closer to a cigarette.

Everything else people describe when they talk about a vape’s “feel” — whether the vapour is warm or cool, whether the flavour is concentrated or airy, whether the throat hit is sharp or smooth — is downstream of that one quantity.

MTL: the cigarette-shaped draw

MTL stands for mouth-to-lung. You draw vapour into your mouth first, hold it for a moment, then breathe it into your lungs — exactly the way most people smoke a cigarette. The airflow is deliberately restricted, so the draw has resistance: you feel a slight pull, like sipping through a narrow straw.

MTL devices vaporise less liquid per puff. The vapour is cooler, the flavour is more concentrated, the battery works less hard, and the device runs efficiently. For adult smokers switching over, MTL is almost always the right starting point because the ritual — the draw, the pause, the exhale — matches what they already know.

RDL: the loose, cloudy draw

RDL stands for restricted direct-to-lung. You inhale vapour straight into your lungs in one motion, like breathing through a wide straw. The airflow is much more open, so there is barely any resistance, the vapour is cooler and much larger in volume, and the flavour spreads out across a bigger cloud.

The trade-offs are symmetrical. RDL consumes noticeably more e-liquid per puff, pulls harder on the battery, and produces a milder throat hit because the vapour is diluted with air. Experienced vapers who chase flavour volume and cloud density prefer it.

Why this matters in disposables specifically

In a refillable device, airflow is a dial: a slider or ring you adjust. In a disposable, airflow is a design decision frozen at the factory. The diameter of the inlet holes, the internal channel geometry and the chimney size are all fixed, and that means the character of the device is fixed with them.

This is why two 12,000-puff devices can behave so differently. A device tuned for a tight MTL draw will sip its reservoir and genuinely last close to its rated count, while the same capacity behind an open RDL airway will drain faster, taste cooler and flatter by comparison, and load its coil harder. The RELX HERC 12000 is tuned on the tighter, cigarette-adjacent end of the spectrum, which is one structural reason its 18ml reservoir and 2,600mAh cell stretch so far in real use — the draw is efficient by design, not just big on paper.

How to describe airflow to a customer in 30 seconds

Use the straw analogy — it works every time. “Narrow straw, tight cigarette draw, cooler vapour, lasts longer. Wide straw, big airy clouds, uses more liquid, battery works harder.” Then ask one question: did you smoke, or are you vaping for flavour and clouds? Ex-smokers almost always want MTL. Hobbyists want RDL. That single question prevents the majority of “this one feels wrong” returns.

When airflow goes wrong

Airflow problems are usually mechanical and cheap to diagnose. A draw that suddenly tightens means the inlet is blocked — pocket lint, dust or a fragment of packaging. A draw that gurgles means e-liquid has pooled in the airway — often after heat exposure thinned the liquid. A burnt edge to the flavour with an otherwise fine draw usually means the coil is running dry rather than the airflow being wrong. Our troubleshooting guide covers the full diagnostic order.

MTL vs RDL: The Practical Differences

Frequently Asked Questions

What does MTL mean on a vape?

Mouth-to-lung. You draw vapour into your mouth first, then inhale it into your lungs, the same motion as smoking a cigarette. MTL devices have restricted airflow, a warmer draw and efficient liquid use.

Is MTL or RDL better for quitting smoking?

MTL, for most people. The draw pattern mirrors smoking, which matters for the habit side of dependence, and the tighter airflow delivers a more cigarette-like throat hit.

Can you change airflow on a disposable vape?

Generally no. Airflow in a disposable is fixed by the internal design at the factory. If airflow changes during use, that indicates a blockage or a leak rather than a setting.

Does more airflow use more battery?

Indirectly, yes. Open airflow devices are usually run at higher power to keep vapour density acceptable, and the coil has more air to heat. Tighter systems operate more efficiently, which is why they often outlast their rated puff counts.