Mini Butterball WF-501B Ultra Violet 395-400nm detector Flashlight for Spot Scorpions Pet Urine Leak ,Minerals Detector led 395-410nm ultraviolet Flashlight. Aluminum construction, with knurled grip. "O" rings for water resistance (not submersible). Essential tool for law enforcement, postal inspections, customs, medical forensics, HVAC repair and so on. power sourse: only 1pc 18650 Lithium-ion Battery (Not included). Great for checking notes, credit cards, fluorescent inks (invisible inks), cracked glassware, or even crime scene.