Model Name T500-44MM???? ???? Bluetooth 4.0 + 5.0 LE ( Dual Connectivity ) ???? Optical Heart Rate Sensor With Dynamic Heart Rate Real Time Monitor ???? Different Sports Activities To Calculate Heart Rate / Calorie Count ???? BT Calling / Message / WhatsApp / WeChat Notification ???? Metallic Aluminum Body ???? Battery Backup Standby Time Upto 1 - 2 Days ???? Charging Time Upto 2 to 3 Hours ???? Square 2 Pin Box Charger Included In the Box