EASY TO USE: ON / OFF only by rotating the light head with one-handed easy Easily attaches to anything or everywhere with chain Especially 5mm white led impervious to shock with a 100, 000 hour Using 3Pcs LR41 button batteries included So nice keychain light for dog walking light, reading, camping, hiking, light or suitable everyday carry for walking up or down stairs, or getting up at night, belongings MIRCO TINY SIZE: Super only 1.3-Inch length, adds no bulk to keychain as kids students or parents, Birthday, Christmas, Valentine ' s Day, Mother ' s Day LONG: high bright about 15, Usable light up to 12 hours of use and can be seen from up to a mile away at night