Upgrade 0.95" Color Screen: Bigger screen displays a comprehensive and obvious activity information; Simply lift your wrist to view directly the time and tap the button for steps, heart rate and other activity information; Also it can not only remind you via vibrating when your phone receives calls, messages or other notifications such as from Facebook, Twitter, or WeChat, but also displays details on the screen directly, such as readable content of massage and name or ID of the caller etc Upgrade 135mAh Battery Capacity: With built in 135mAh Lithium ion polymer battery, long battery life, charge it once, the battery will last for over 20 days under normal use; With a skin-friendly strap made from soft thermoplastic elastomer, and a secure locking mechanism that makes the Mi Band 4 comfortable to wear during low and high intensity activities Bluetooth 5.0: Download "Mi Fit", Connect via Bluetooth (Android 4.4/iOS 9.0 phones or later) to see notifications from app messages (WhatsApp, Facebook, etc.), incoming calls, caller ID, SMS and activity goals; Note: Currently only support Chinese and English, Before the device is paired with your phone, its default language is Chinese; If your phone language is English, then the device shows phone language regardless where you are 50 Meters Swimming Waterproof Smart Band: 50M Waterproof Rating, Xiaomi Mi Band 4 can work well 50m under water, which can fulfill all your daily routines, whether you are surfing, swimming or running in the rain; 5ATM (Swim or Shower in not-hot water), showing swimming time, speed, distance, calories and other data Heart Rate Monitor and Sleep Monitor: This fitness tracker can track your heart rate 24 hours automatically and continuously. You can check the dynamic curve chart of your heart rate throughout the day on the App by analysing the data thoroughly such as sleep time, sleep depth and sleep awakening, driving to improve sleep quality