This type of flashlight is used for Money Detector, Credit Card, cash (currency), detection Glass Break Detection, Bugs/Insect Detection, Minerals Hunting, Automobile Air Condition, Fluid Leaking (Freon), Police use it for scanning the crime scene. 1 21-LED UV flashlights in black body finish Specifications: Bulb Type Longwave UV LED, 395nm nM Bulb Life 100,000 Hours Body Material Aluminum with "O" rings for water resistance Battery Require 3 x AAA Alkaline Battery (Not Included) Battery Life Approximately 20 hours on 3 AAA batteries Switch Type Press on, Press off from rear cap