Its a commercially bought bicycle lamp. Here's a stock photo.
The build quality of this light is amazing. I did swap out the silicone o-rings to more robust rings. the stock lens is a 3mm lens, but since the diameter is only around 34mm, I calculated it would handle the pressure of recreational dive limits (but not quite with a protection factor of 2).
I was further sold on the lamp after I saw a bunch of beam-shots from
taschlampen-test.de
The switch on the stock light is a momentary-on switch and what I believe to be a PWM driver. So I replaced the switch with a reed, then I placed a magnet in (of all things) a purge button that I cut out of an excess plastic regulator face-plate. It works like a charm
Since it was a bike light, it had mounting hardware, which I attached to a PVC plate then used the velcro strap that came with the kit as a strap for my hand.
For the input of all the folks here and at CPF (that would be you, packhorse, and lucca) and the greatly detailed work of wquiles, and even the at times heated debates seen in threads of H2Odoctor, I've learned a lot. Thank you. More feedback would be greatly welcome.