Shelf

Battery Formats

18650, 21700, 18350 and the other cell formats, and what each one changes to the size and runtime of a mod.

Every feature on this shelf

21700 mod, what moving to the bigger cell really changes

A 21700 mod against an 18650 one, size, weight and run time worked out from Molicel data, current draw, chargers and when to stay with 18650. 31 August 2026

The Fumoir in brief

Here a mod is judged on what it is worth after months of use: how the chipset holds up, the quality of the contacts, the parts you can still find.

Features are written by Paul-Henri Fage.

Meet the Fumoir

The Fumoir shelves

The Fumoir overhang checker

Does your atomiser stick out past the mod? Enter both widths and the verdict appears straight away.

Atomiser diameter

Mod width at the 510 connector

Overhang per side: 1.0 mm
Verdict: Slight overhang

The atomiser sticks out a little on each side, mostly noticeable from the front.

Measure the atomiser at its widest point and the mod where the connector sits. Our reference points: up to 0.5 mm per side the pair looks flush, up to 1.5 mm the difference stays slight, beyond that it becomes marked.