It should be fine on a keychain, although you may find yourself wanting to replace lexan lens with a glass one at some point down the road depending on how much and where your keys are stored, because it seems that any non glass flashlight lens will ultimately get scratched when used on a keychain for EDC, at least in my case. I stopped using my favorite light, my turbo nano mate, until I address the issue of the plastic lens that it uses with perhaps some sort of lens protector. I use my Arc AAA at the moment. I'll probably pick up a different lens for my LSL as well as my search for the perfect keychain light continues.
