Pyle Bluetooth Smart Heart Rate Sensor for iPhone and Android Phones, Works With Polar ALA Coach & MotiFit Strava Apps Bluetooth LE Sensor Bluetooth 4.0 Wireless Technology - Effectively Tracks and Records Heart Rate - Does Not Interfere With Sport Performance Measures Your Heart Rate - Works for iOS Devices (iPhone 4S, iPhone 5, iPad, iPad mini) and Android Devices 4.3 & Later (Samsung, HTC, Sony, LG, Motorola)-Soft Fabric Strap for Comfort Heart Beats Per Minute Wirelessly Transmitted - Monitor Your Health - Improve Your Performance and Make Your Training More Fun Download the App APA COACH+ free via App Store - Provides Instant Wireless Feedback and Data - Batteries 1 x Button Cell (Type: CR2032) Also compatible with other training and fitness APPs on the market - Easily and Comfortably Wraps Around Your Chest