Smartphone notifications, touchscreen functionality, activity tracking, custom goal and alarm settings, customizable watch faces and watch bands, music controls and micro apps Powered with Wear OS by Google, a trademark of Google LLC. Compatible with Android OS 4.4+ (excluding Go) and iOS 9.3+. All devices have Bluetooth(R) 4.1 Low Energy and Wi Fi 802.11 b/g/n Touch screen Movement Case Diameter: 43mm