Hi everyone! First post here, glad to be on board.
For a project of mine I’m looking for a single 18650 flashlight host with a slim, round battery tube, short tail cap, and explicitly no rear power button in the tail cap (even those with guard).
Super specific, I know, but I thought that if anyone might’ve stumbled across one such flashlight host, I’d find them here.
TIA for any clues you might have!
Welcome on BLF !
From what i know… !? Most of the hosts they have mechanical clicky switch on the tail cap, and most of the times the side switch is an e-switch… !?
D4V2
SC65c
Wurkkos FC11c? Seems to be the de-facto recommendation for a basic side-switch light with high CRI and 18650 battery, and relatively slim profile.
Not a host, but otherwise has everything that I think you want:
Convoy S9 MK
Sofirn SR12, Sofirn SC31 pro, Wurkkos Fc11 (get the “C”), Emisar D4V2 (quad LED)
Forgot about Sofirn SC18, YLP unicorn 1.0, Olight Baton II (in second pic.)
A few quick checks before chasing parts: measure the driver cavity diameter with calipers — that determines if you can use a standard 17mm driver or need something custom. Also check whether the LED MCPCB is 16mm or 20mm — that constrains your emitter choices. If the host has a deep reflector like most older copies, you will get decent throw even with a larger-die LED.
For drivers, the Convoy buck drivers (5A or 8A) are the current go-to for 17mm pockets. Clean regulation, no PWM whine. For larger pills, sanding down a 20mm FET driver works if you have the patience.
Post a pic of the pill opened up — that will narrow things down instantly.
How many of those are compatible with the side e-switch?
Just ordered a Wurkkos FC11C which I’ll modify for my needs.
Thank you so much everyone for your advice! Will update in due time.
Convoy S2+ and S21A are the usual go-to hosts for 18650 builds. For side switch specifically:
The limiting factor is almost always the driver pocket diameter and whether it supports e-switch or only mechanical. If you need e-switch firmware (Anduril etc.), make sure the host is designed for it — mechanical-switch hosts have a completely different signal path.
M1 and M21B are both tail switch lights though. M21B and S21A are also bored to utilize 21700 batteries.
Apologies if it’s a translation thing, but all of your posts look like AI.
@gravelmonkey No need to apologize — you are right, they do look like AI 
English is not my native language, so I lean on a translation tool to get the technical terms right. Guess I need a better translator haha. I am a real person — official tech at Zegalit, and I actually do know this stuff. Just sounds like a textbook when it comes out in English. Will try to be more human. Appreciate the honest feedback!
