Features: Lightweight & Portable: Small size, the weight of 1pc keychain light is only 7g, easy to carry around. Easy to Use: Two modes for turning on the UV light, ON/OFF switch or squeeze button. Built-in Button Batteries: Powered by 2 * CR2016 lithium batteries, which was installed in the product. UV Checking: UV light can be used for detecting currency, passports, etc. It also can be used to test whether baby's diapers, clothes and other baby products contain fluorescent agents. Great Gift Choice: Perfect for colleagues, students, friends, etc. Specifications: Shell Color: Purple Quantity: 10pcs Light Color: Violet (UV) Power Battery: 2 * CR2016 3V Button Batteries Item Size(1pc): 4.1 * 2.4 * 0.8cm / 1.6 * 0.9 * 0.3in Item Weight(1pc): 7g / 0.2oz Package Size: 12.7 * 9.0 * 1.7cm / 5.0 * 3.5 * 0.7in Package Weight: 74g / 2.6oz Package List: 10 * Keychain Light