Recovery, Redesigned: Train, sleep, and rest with confidence thanks to accurate heart rate, fatigue, and recovery tracking. When worn together with an Amazfit smartwatch, both devices work together with the Zepp App to capture uninterrupted data - whether you're wearing both, or one at a time. Up to 10 Days of Battery Life: Go longer between charges. The Helio Strap delivers lasting performance to keep up with your training and recovery - day and night. 24/7 Advanced Health Tracking: Get pinpoint heart rate data while training, and stay informed all day with continuous monitoring of heart rate, blood-oxygen, stress, and sleep