Product name Haylou RS4 Max Dimensions 48.3x39x11.4mm Working temperature -10 - 45°C Resolution 320x380px Colors Midnight Blue, Starlight Silver Bluetooth V5.3 Water-resistance grade IP68 Battery life 9 days (24/7 heart rate monitoring) Display 1.91-inch LCD display Synced data platform Haylou Fun Battery 270mAh Supported devices Android 6.0 and above, iOS 9.0 and above