Vktech&reg; OLED Smart Watch Bluetooth 4.0 Pedometer Step Walking Distance Calorie Counter Sport Tracker Sleep Monitoring Stopwatch Black Pedometer/Distance Course/Sleep Monitoring/Bluetooth/Stopwatch Double bright screen/Long Bluetooth standard: 4.0EDR Material: OLED Screen with Silicone Strap Size of Product: 43mmx17.1mm/Ring thickness: 9.22mm/Screen size0.91Inch