WEGO Elite Activity And Sleep Tracker With One Button Function Toggle, Powered By The Map My Fitness App Powered by the map my fitness app Battery status indicator built in Clock 1 button functionality toggle between the different modes press and hold 3 seconds to enter or exit sleep tracker mode Battery included user replaceable CR2032 Compatibility iPhone 4S and newer iPad 3rd generation and newer iPad Mini and newer select Android devices running 4.3 and later for a full updated list of compatible devices Visit joinwego.Com/compatibility