Which Surefire KL1 generation is this head?

[laxref]

Is this a 3rd or 4th Gen KL1? Found in my drawer of old bits. Going to toss is on a MDC 1 cell body for a nice general walk around light.

[ampdude]

Looks like the square beam Luxeon 3 model. People assign different gens to KL heads for odd reasons. This would be the version right after the original finned head with the round bezel and semi-crenulated bezels. Some people call those gen 1 and gen 2 (I don't). If it has a rounder beam it's the later Seoul version, but I'm guessing not based on the serial. I'm having a tough time remembering if any of the Seouls came with apheric lenses, I don't think they did, I think they were all reflector based. None of these were ever my favorite LED heads. I do keep vintage E1L around (Luxeon 3 aspheric lens just to remind me of the good old days and laugh at the beam a bit. Try yours out and see!

[laxref]

Definitely square beam. I like it for a small handy walk around light. When I first got it, I used it on on old E2 Executive. I tried looking it up early, but the Gen this and Gen that was hard to sort out and most of the pics in the threads for way back then aren't there to reference.

[ampdude]

Definitely square beam. I like it for a small handy walk around light. When I first got it, I used it on on old E2 Executive. I tried looking it up early, but the Gen this and Gen that was hard to sort out and most of the pics in the threads for way back then aren't there to reference.

Yea the Gen stuff is usually tacked on by people who aren't familiar with every revision or change in design or specs (internal or external).

It's not really a useful concept with older Surefire lights. And for certain not with newer ones.