Alright, here's more pictures, I have to retrieve it from its hiding place, I really can't afford to lose it if someone break into my place. I don't think money can replace this rare gem.
I have no idea what's a KT-6 but the PK1 is significant bigger than the M6 KT-4 head. The LED opening is slightly bigger than 11mm. As for the mod, I probably turn a piece of sink from copper and a 3A XML, this will keep the PK1 head untouch. The reflector is a part of the head it is non removable.
The PK1 sink is very thick which is important because the poor Lux V 5W is over-driven by a step-down converter. The output current to the LED is about ~1350mA @ 6.5V. Input is
[email protected]. So the output at the LED is 8.78W, and current draw of the battery is 10.42W.Efficiency is about 84%. Not bad. But the 5W LED is being over-driven badly, it got very hot quickly with the module detached from the head.
The beam is nothing to shout about, the wide reflector produce a very tight spot. Something I have never seen before, it is as if the light is coming from a P60 XR-E reflector light. The 5W is a loser for today standard.
As to where it came from, I have no idea, my friend said he bought it from a Korean. Which I believe a lot of PK items are traded there. The seller also has numerous rare Surefire such as A2T, L6T, PK2. So I guess this is a different PK1.