42mm (1.2-Inch) AMOLED Color Full Touch Screen & Resolution 390 x 390 Multiple & Customizable Watch Faces: ALS Ambient Light Monitoring - Automatic Screen Brightness Adjusting Stress Test: It Supports The Tracking Of Stress For 24 Hours. Heart Rate Monitoring: Continuous Heart Rate Monitor (Throughout The Entire Day) Trusleep Monitoring: Monitor Sleep Time, Identify Indicators -Deep Sleep, Light Sleep, Rapid Eye Movement Etc. Provides Sleep Quality Assessment & Improvement Recommendations