boAt Lunar Discovery w/ 1.39" (3.5 cm) HD Display, Turn-by-Turn Navigation, DIY Watch Face Studio, Bluetooth Calling, Emergency SOS, QR Tray, Smart Watch Operating System is android Special Feature is DIY Watch Face, Daily Activity Tracker, Emergency SOS, GPS Navigation, Phone Call Connectivity Technology is Bluetooth Wireless Communication Standard isBluetooth Battery Cell Composition : Lithium Polymer