I modified the head of a Surefire Winelight to host a 2W Nichia UV LED (shhh! Doesn't exist!). The rear collar of the stock head was removed, and the hole bored out to accept the face-mounted LED. The machined reflector in this head is the primary heat sink - lots of surface and lots of mass. I then coarsely bead-blasted and re-polished the reflector for an even flood beam. Wavelength of the emitter is around 370nm - barely visible to the human eye.
Looking into the back of the head where the collar was removed.
