While I doubt the “world’s smallest” claim, the Slughause Bullet 02 Mini Tactical LED Flashlight is tiny. Put this tiny LED flashlight on your keychain and forget about it, until you need a flashlight of course. Not only is this a tiny flashlight it is also waterproof, fireproof (??), tough (aluminum), and bright enough to be seen over 1 mile away (20-lumens). 10mm x 26mm tiny and only 5-grams.