Description: Product name: M4 Smart Bracelet Color: blue, black, red (optional) Bluetooth-compatible: 4.0 Screen size: 0.96 inches Battery: 3.7V, 90mAh Theoretical standby time: 10 days Theoretical working time: about a week Waterproof: IP67 Packing weight: 50g Introduction: 0.96-inch color screen, clearly visible in the sun, monitor your sports information at all times, IP67 waterproof, you can wash your hands or wear it in the rain, but it is best not to wear it for swimming Features: The principle of photoelectric signal detection records your heart rate and continuously detects your heart rate for 24 hours. Automatically record steps and burn calories. You can choose an exercise program that suits your life rhythm, nothing more than sweating after exercise. Sweat can relax, exercise, and make yourself a happier version of yourself. The bracelet will automatically detect your sleep and generate a sleep report. With IP67 waterproof performance, it is completely fearless in rain and water environment, allowing you to enjoy the joy of life. When you forget the time, the bracelet will vibrate gently to remind you to get up and wake up. Note: 1. After receiving the watch, please charge it first. The watch is out of stock after a long logistics. 2. Do not wear the smart bracelet in sea water, hot water or warm water! 3. Wearable devices monitor human activities through electronic sensors, at the level of consumer electronics. Some deviation is normal. Users must treat data objectively.  4. Please do not compare with hospital equipment, not medical equipment! Do not buy to check health (heart problems, blood pressure problems) it is not for professional use. for reference only. Packing list: 1 x M4 Smart Bracelet 1 x charging cable 1 x instructions 1 x packing box Note: 1. Due to manual measurement, please allow 1-3cm error. Make sure you don't mind before bidding. 2. Due to the difference of different monitors, the picture may not reflect the actual color of the product. Thanks.