Amazfit Helio Ring Wearable Fitness Tracker - Original 1 Year Warranty by Amazfit

Outer ring: Titanium alloy Inner ring: Resin Ring Size (Circumference) : 8(19mm) | 10(20mm) | 12(22mm) 10ATM Water-resistance Grade, 3-Axis Acceleration Sensor, 3-Axis gyroscope Sleep & Recovery Coach, Stress & Emotion Monitoring BioTracker PPG Heart Rate Sensor, Temperature sensor, EDA sensor Up to 4 days Typical Usage, 1H Wireless Charging Sports Data Tracking