This is an arm type sports monitor for measuring sports parameters such as heart rate, step count and step frequency. This device is built with powerful motion sensors and accurate motion algorithms to calculate motion and body parameters, and connects to devices such as cell phones, sports equipment, etc. to manage motion data. Model:HW807 Main function: Measure heart rate, step count WIRELESS: Bluetooth 5.0, ANT+ H R V : Support Storage: heart rate 8 hours, steps 1 week Display: LED multi-color light Battery: Rechargeable lithium battery 90mAh Battery life: continuous measurement 16 hours Colour:black :ABS Package Contents: 1 x Bluetooth heart rate arm band Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.