Screen size 1.39 inch Special feature Sleep tracking Round shape Age range (description) Adult Smartphone compatible peripherals Display type Digital Type of USB connectors   About this item Battery Life: 16 days ultra-long battery life 5ATM Water Resistance: Up to 50 m water resistance 32 g ultra-light weight design Blood Oxygen Testing: Checks your blood oxygen saturation to give you a better picture of your physical health Heart Rate Monitor: 24-hour real-time heart rate monitoring Sleep Tracking and Score: Analyse your sleep quality by recording complete sleep data such as deep sleep, light sleep and sleep duration to help maintain good sleeping habits. Activity Tracking with 117 Sports Modes including running, cycling, swimming, hiking, rowing, jump rope, yoga, climbing, sailing, football, skating and more Vital Sign Monitoring: Analysis your vitals to understand your physical condition and reduce chance of injuries from exercising when fatigued Stress Monitoring: track and monitor your stress and give you suggestions to ease and recover from stress GPS Support   model ‎BHR4723GL