Start Your First Step Into Smart Fitness Amazfit Bip U with smart features like 1.43” (3.6 Cm) Large Color Screen, Blood-oxygen Level Measurement1, 5 ATM Water-resistance, 60 Sports Modes, and High-precision GPS3. It is time to invest in you with Amazfit Bip U. The watch accurately monitors your sleep stages, including those of deep sleep, light sleep, REM, awake time, and afternoon naps⁷, and interprets the characteristics to provide you a sleep quality score and insights for improvement.