You can include 16340 support, but don’t waste any space on building in a charger.
If you really want to stand out, include red or green laser options. If you can price those models at 100-150 (still potted and stuff), you’ll compete quite well with the $300 Streamlight TLR series :+1:
Already mentioned: Potted. CR123 support. Quick unscrew to swap batteries. Mechanical switch, with no modes. It should also be just as waterproof as the pistol. The beam pattern isn’t super important - we know size is limited, so don’t worry about it too much. A TIR is probably pretty good here, if you can get something like the Olight S1 batons do. Otherwise, some sort of shallow orange-peel reflector should be fine. And something neutral (4000K to 5000K) with a bit of high CRI is nice, like a Nichia 219C CRI90 or SST-20 CRI95. That will also stand out from the 7000K 70CRI offerings available.
If you actually hit most of these points, I’ve got a friend who keeps eyeing the TLR-2G that would snatch one of these up, and he’s the kind of guy who basically sells his friends on all the products he likes.