LED Keychain Flashlight - Teardrop Slide/Squeeze Dual Switch - Ultraviolet Black Light 385 nM True-UV Dual Action Switch for easy momentary or constant on operation Check currency bills, identification, etc. Detects all 3 colors of bank note security fluorescent fi Uses lithium button cell batteries - easily changeable (included, preinstalled!) Super Rugged Construction - Practically Unbreakable Many hours of continuous runtime off of a single battery set