Appearance material: zinc alloy + IML process case, electroplated anti-fingerprint strengthened mineral glass mirror Charging time: 4 hours Duration of use: 3---10 days Waterproof grade: IP67 waterproof Compatible system: IOS, Apple IOS 10.0 or above / Android system, support Android 4.4 and above FLASH memory: 128MB 130 sports modes Screen size: 1.46 inch IPS full viewing angle color screen Resolution: HD 360*360 Bluetooth: Dual Bluetooth 5.0 Heart rate: Zhan Heng BD1662_I2C (true heart rate true blood oxygen) Charging method: wireless charging Battery capacity: 3.7V/315mAh (lithium