SMART RING TRACKS YOUR HEALTH - Smart Ring size smaller then US standard size. Smart Ring's data can easily track your sleep, activity, body temperature and more through the mobile app without any subscription fees. Please update to the latest firmware version. 4 CHIPS FOR ACCURACY - The KEREEP Smart Ring has been improved based on over 20,000 user experiences and utilizes 4 chips and instant capture technology to provide accurate vital sign data. For sports or aviation use only, not for medical use. SENSELESS WEARING FOR EASY SLEEP - Made of lightweight, skin-friendly, high-strength titanium, KEREEP smart rings provide you with monthly/weekly/daily reports of various sleep stages, such as deep sleep, REM sleep, light sleep and awake. IPX8 & WIDELY COMPATIBLE - Water-resistant to 330 feet, our smart ring is not afraid to swim and can be worn in the shower. The smart ring supports Android 5.0 and iOS 10.0 and above. LESS CHARGING, MORE TRACKING - Truly wireless charging technology that takes only 1 hour to charge and lasts up to 7 days. Supports adding different groups and member accounts to share health data reports with family and friends