I have one that I have used on my 6P/9P,with Cree LED Drop-in,L5 and KL3 as well as my M3T with Arcmania Turbohead Module, and it works just fine! I tied it on the 6P with a P60 bulb and thought it was unimpressive. With all the above listed lights, I really like this tailcap...and for the price, I just had to at least try it!!! My friend who seems to love talkin sh!t about my flashlights fell victim of the G&P Strobe tailcap! He was decending the stairs with me behind him, I held the button down on the 6P loaded with the Cree drop-in module and G&P Strobe Tailcap.......BAM.....BANG BOOM BOOM BOOM..... WHAM!!! Down the stairs he went.(only about 3-4 stairs)
I thought he was crying and felt bad for a second UNTIL he rolled over Laughing his A$$ OFF!!! "You finally got me...I guess its payback for all the crap I give you about your lights" he said. Later that night he was hitting me up for what light and accessories to get. HHmmmm.....which one did he choose? 6P with G&P tactical bezel and tailcap!!! I do wish however the strobe (Hz) was somehow adjustable...strobes a little to fast to be truelly effective, but is still disorianting. There is also a bit of a noticable very fast flicker with some lights while in the "Constant ON" mode. Not very noticable. I was told it happens because of the PWM circuitry.
Is it bad to use on bulbs? Would it shorten the lifespan of the bulb?
Is there any reason it would be bad to use for LEDs?
ANYWAY.....for the price, I think you'd like it. If not sell it!