Note: D21 Smart bracelet product details URL: https://www.youtube.com/watch?v=uZtmCWlJZw0 Function: Model: DFit D21 1.Model: D21 Smart Band 2.Memory size: 256k 3.Acceleration sensor: triaxial accelerometer 4.Strap: medical silicone 5.Display: 0.66OLED screen 6.Vibration motor: cylindrical vibration motor 7.Operation way: touch operation 8.Battery Capacity: 80mAh (Standby time will depend on the actual using situation.) 9.Standby Time: About 3-5 days 10.Waterproof : IP65 11.Bluetooth version: Bluetooth 4.0 12.Rapid brush Metro BUS, can be customized set up the city (Built-in NFC chip) 13.Support System:Android phone(Android 4.3 or above and bluetooth 4.0), and iPhone (iOS 8.0 or above and bluetooth 4.0) The main function: Heart rate monitor, caller ID, text messaging, micro-channel, vibration Step count, distance, calorie consumption Time display, sleep monitoring, camera, anti-lost reminder Smart alarm clock, smart unlock Sports information sharing Firmware Upgrade Sedentary reminder Motion Tracking Precautions: This product contains magnetic parts, has installed a pacemaker or implanted electronic devices or metal objects, please do not use this product. When such wear, symptoms appear, please stop using the product immediately. If you use sub-standard power charging will shorten battery life, and even damage the battery. Our bracelet sealed process, anti-sweat, to meet the daily water, such as hand , etc., but does not support swimming, diving grade waterproof. Package include: 1 * Bracelet 1 * Charging Cable 1 * User manual (note:English)