I think it's using a K2 Flipchip, if it's the same "C4" that's used in the Super Tac.
-dan
Mark, are you getting decent runtime with eneloops, and how much estimated brightness? Thanks.
Mark,
Can you tell if it is a K2 Flip Chip as claimed or is it actually a Cree XRE? Photos of the bezel of this light at Brightguy kinda look like it might be a Cree..
The Super Tac and Stinger LED are using K2s and so are the other lights.