SPECIFICATIONSActivity Tracked: Activity Tracker,Steps Tracker,Distance Tracker,Calorie TrackerBattery Capacity(mAh): 15mAh (7#~9#), 18mAh(10#~13#)Brand Name: COLMICase Material: SteelCertification: ce,FCCChoice: yesDisplay screen: YesHigh-concerned chemical: NoneItem Weight: about 3.3gMetrics measured: Heart Rate Monitor,Sleep Monitor,Blood Oxygen Monitor,Stress MonitorModel Number: COLMI R12NFC Support: NoOrigin: Mainland ChinaWaterproof Grade: 5ATM COLMI Smart Ring No.1 in sales on AliExpress, and is far ahead. Note: 1. For best performance and accuracy, we recommend wearing the COLMI R12 on your index finger.2. Please measure the circumference of your finger before purchasing, and make sure the rope or paper strip fits snugly against your finger, avoiding being too loose or too tight. (Please use a thinner piece of string or paper strip to measure the size. If the measuring tool is too wide, the measurement will be large.)3. How to start: Use the included wireless charging to charge COLMI R12. The heart rate light will light up to indicate successful startup. Then you can use the APP Qring to connect the COLMI R12. COLMI Smart Ring - R12 with Wireless charging Innovative Technology: COLMI R12 uses the latest display technology, with a screen and touchpad built into the ring. Browse your health statistics with simple gestures, making your smart ring both responsive and stylish.Wireless Charging: Enjoy the convenience of wireless charging with the R12.Health Tracking: Stay on top of your health with continuous heart rate, sleep, and activity monitoring. Plus, its water-resistant design ensures durability, making it perfect for everyday wear, rain or shine.Embrace innovation and elevate your wellness journey with the COLMI R12 Smart Ring. COLMI official store Authentic COLMI smart watch are engineered and manufactured with high-quality materials, and they're always quality-tested before they leave our factory. Since counterfeit or fake devices are not built or tested to these standards, they might perform poorly or malfunction. So, we recommend buying devices sold only by our official store. Brand Story COLMI was established in 2012.Slogan: Your first smart watch.Young and simple, but never naive.Mission: Provide cost-effective smart electronics.