I recently acquired a Surefire G2 Nitrolon which comes with a 65 lumen lamp assembly.  This thing is blinding and if you should point it at yourself, you’ll be seeing spots for a few minutes.  Not being content to leave well enough alone, I ordered the P61 lamp assembly, which is rated at 120 lumens. 

I wasn’t going to try the “shine it in the eyes test”, though, given my experience with the stock lamp.  However, I still managed to blind myself.  I had it pointed down when I turned it on, but didn’t think about the reflective qualities of white paper.  The paper reflected enough of the light to leave me blinking at the red spot in my vision for a few minutes.  I think the reflected light from the paper was at least as powerful as the original 65 lumen lamp.

I think I’m going to keep this one around for handling things that go bump in the night.  If the light doesn’t vaporize them, I’ll at least be able to completely identify the target. 

After experiencing the 120 lumen lamp, I can’t even imagine what the M6 Guardian would be like, with its 500 lumen lamp.  I suppose you could use it for interplanetary signalling if you don’t go up in a ball of flame from the heat it puts out.  Surefires get very hot very quickly.