Wear it while swimming & surfing. Water resistant up to 50 meters. With a 5ATM rating, Mi Band 3 provides greater water resistance that allows you to do more. Monitor activity in real time New secondary activity tracking screen. Whether you’re running, biking, or walking, you can always check your heart rate and speed on the go. Set a goal for yourself & work to achieve it. Goal reminders. Mi Band 3 will notifiy you upon reaching your target for the day.