Xavier,<br><br>I had some heat shrink out tonight (getting a couple of new climbing ropes ready for use) and tried some of appropriate range on one of my Photon IIs. No problem with the heat, but I am very careful to direct the heat (paranoia about ropes) - YMMV. It was not especially secure due to the slick surface of the plastic and various lengths gave various compromises with regard to effect on the projected beam. I was using a Turquoise Photon II to experiment with - it has a fairly wide beam angle (30 deg) - and I had to leave all of the dome exposed in order to get substantially the same beam as uncovered. The narrower beams (white is 20 deg; yellow and orange are 15 deg) should be a little less affected, but I didn't test them because the adhesion was unsatisfactory. <br><br>I carry a red in my left pocket and a turquoise in my right pocket every day with coins, knives, micra, keys, etc tossed and have had zero scratches so far. The diameter of both these LEDs is fairly uniform at 0.187 inches +0.0003 / -0.0005 at a quick check. That's not a clean metric size, but is very close to 3/16 inch (0.1875). A #13 drill bit is 0.185 inches and a #12 drill bit is 0.189 inches. You could use one of those sizes to drill thru various materials (the actual hole diameter will vary with the material, but usually will be a little larger than the bit size for various reasons). Find something that works for you and trim/file away the excess on the outside - fasten as below:<br><br>What about trying a close-fit aluminum or brass tubing from a hobby store (K&E brand name, I think)? Find one that is a close fit (3/16 inch inside diameter), trim to length, and use an appropriate adhesive on it? cyanacrylate (sp?) aka super glue might work; a plastic-use-designated epoxy would for sure. <br><br>I've thought about turning a small piece of aluminum as an LED protector with an internal "reflector" cone appropriate for the beam angle, but heck, it's just an idle thought - I have "real" flashlights - these are fine for my use as-is. But if you know someone with a small lathe, maybe they will turn up a couple of prototypes for you...?<br><br>Hope that helps.<br><br>Tom