7-day battery life, water-resistant to 50m Compatible with ios 15 or higher and android os 9.0 or higher Move more: on-device heart rate display via bluetooth, built-in gps, 40+ workout modes, daily readiness score, active zone minutes, 24/7 heart rate, all-day activity tracking, cardio fitness levels, automatic workout tracking, workout intensity map and mobile reminders Comfortable connectivity day and night: google maps, google wallet, youtube music control, call, sms and smartphone app notifications, vibrant color touchscreen with customizable clock face, timer and stopwatch Sleep better: automatic sleep tracking, personalized sleep profile, daily detailed sleep score (premium version), smart wake-up vibration alarm clock, sleep mode Health by fitbit: daily stress management score, mindfulness classes, relaxing breathing classes, blood oxygen saturation (spo2) monitoring, resting and high/low heart rate notifications, ekg and irregular heart rhythm notifications Includes 6-month premium membership for deeper insights and guidance, exclusive workouts, mindfulness classes, and more Included in the box: fitbit charge 6 tracker (includes small and large straps). small wristband sizes are 140mm - 180mm, large wristband sizes are 180mm - 220mm. also includes charger (compatible with fitbit charge 5, not compatible with other models)