MULTIFUNCTIONS: - Pedometer:Steps,Calories,Distance - Heart Rate Monitor - Exercise Monitor - Menstrual Period Monitor - Remote Photograph - Sleep Tracker HARDWARE: Bluetooth:5.2 Charging Type:Magnetic Charging Full Charge Time:About 1-2 Hour Ring Battery:18mAh APP:Da Rings Standby Time:One full charge gives you(3-5 days of working time) iOS 10.0 or above,Android 5.0 or above Ring Material:Stainless Steel Packaging Accessories: Smart Ring*1 Charger*1 Manual RING SIZE: #7 (Ring inner diameter:17.3mm/0.68",Ring circumference:54.3mm/2.14") #8 (Ring inner diameter:18.1mm/0.71",Ring circumference:56.9mm/2.24") #9 (Ring inner diameter:18.9m/0.74",Ring circumference:59.5mm/2.34") #10 (Ring inner diameter:19.8m/0.78",Ring circumference:62.1mm/2.44") Weight:5g - IP68 Waterproof - DO NOT suitable for hot water bathing,diving,water-related work. Any questions,please kindly contact us,we would always offer best solution to you.