Up to 40 hours of battery life with fast charging (50% in 15 minutes). Advanced Fitbit metrics, including heart rate, sleep tracking, and readiness scores, along with over 40 workout modes. Design & Display: 45mm case with a 1.4" (456x456 pixels) domed display featuring thinner bezels, 3000 nits brightness, and 50m water resistance. 6 Months Warranty