The 2.5D colourful touch screen offers you with the stunning visual experience, engaging interface and smart message notification. Every Unique Side of You Express yourself by giving your device as much personality as you have. HUAWEI Watch Face Store1 offers various watch faces in different styles of sports, cartoon, intelligence and hi-technology for your selection. The style changes with your mood. Easy Charging, Longer Usage Free you from different cables and chargers. The built-in USB plug of HUAWEI Band 4 fits in general USB chargers so you charge it anywhere and anytime.2 A single charge powers the band with more than 6 days of usage time.3 Oxygen Saturation Detection Blood oxygen saturation (SpO2) is one of the important vital signs that can reflect the oxygen supply of the body. HUAWEI Band 4 supports single-time SpO2 level measuring, helping you detect the level of oxygen in the blood whenever and wherever you need.4 Smart Heart Rate Tracking Thanks to the professional optical devices, processing chips and AI algorithm, the HUAWEI TruSeen™ 3.5 monitors your heart rate with accuracy. It also provides intelligent reminders via vibrations if your heart rate exceeds the maximum average heart rate.5 In the night mode, the invisible light ensures less distraction for your better sleep. Care For You Better Sleep Healthy sleep is the basis for healthy living. HUAWEI TruSleep™ 2.0 tracks your heart rate during sleep to recognize the four phases and analyze the sleep quality. More than identifying 6 types of sleep problems, it also provide suggestions6 to help you enjoy better sleep.