Specifications Hign-concerned Chemical:None Waterproof Grade:5ATM Model Number:R10 Display screen:No NFC Support:No Activity Tracked:Activity Tracker,Steps Tracker,Distance Tracker,Calorie Tracker Metrics measured:Heart Rate Monitor,Sleep Monitor,Blood Oxygen Monitor Certification:ce,FCC Battery Capacity(mAh):14mAh Color:Silver, Gold, Black App:QRing Type:Smart Ring For Men Women Material:Stainless Steel Type 2:Heart Rate Blood Oxygen Dual PD Chip Charging Method:Wireless Charging How to choose your size - Measuring Finger Method Step 1: When measuring,please choose a thin,non-stretchy wire and wrap it around your finger and mark it with a pen or other tool. Step 2 : Straighten the thin wire and measure its length with a ruler and shop against the ring specifications bove. Warm Reminder : Typically, sizes 7-8 are suitable for women and 9-12 are suitable for most men's sizes. Please measure your finger size before purchasing to avoid inappropriate size Product Parameters Model Name: R10 Smart Ring APP:Qring Chipset: RTL8762 ESF Memory:RAM 104KBROM 512 KB BT: BT5.2 Waterproof grade:5ATM Body MaterialStainless Steel Battery: 14mAh(18mAh for size 11 and above) Charging MethodWireless Charging Charging Time: About 1.5 hours Normal Using Time: 3-5days (depending on personal habits) Standby Time: 7days-10days Supported Systems :Android 5.0 and above iOS 10.0 and above Ring sizemm) : No. 7, 17.5 mm; No. 8, 18.3 mm; No. 9, 19.1 mm; No. 10, 20 mm; No. 11, 20.8 mm; No. 12, 21.6 mm; No. 13, 22.4 mm; No. 14, 23.2 mm Sensor : ST LIS2DOCTR Heart Rate Sensor : Vcare VC9213A Major function 1>Daily Activity: Steps, Distance, Calorie Counting 2>Health management: heart rate, oxygen saturation, sleep tracking, multi-sport mode, stress, heart rate variability 3>Other Functions:Remote Photo, Find Ring, Gesture Control, GamesFemale physiological reminders Note: 1. For best performance and accuracy, we recommend wearing the Smart Ring on your index finger. If you prefer other fingers, the middle and ring fingers are also OK. Avoid using fingers that are narrower than the knuckles at the base. 2. The size of R10 ring may not be completely in line with universal standards. Please measure your finger circumference before purchasing and make sure it fits comfortably, then choose the appropriate size. 3. How to start: Use the included charging cable or charging case to charge R10 Ring. The heart rate light will light up to indicate successful startup. Then you can use the APP Qring to connect the R10 Ring. 4. Some models have a protective film on the charging port. Please remove the protective film before charging.