Memory1 Saves 7 days of detailed motion data, minute by minute1 Saves daily totals for the last 30 days Stores heart rate data at 2-second intervals Battery and power5,11 Battery life of up to 7 days. We recommend charging your tracker every few days to ensure you are always tracking. Battery type: Lithium-polymer5 Charge time (0-100%): 90 min11 Quick Charging: 1 day of battery life in 5 min11 Radio transceiver: Bluetooth 5.03 Materials The Fitbit Air housing is made of recycled polycarbonate and PBT plastics.2 The band is made of textile and has a stainless steel buckle. Packaging uses 100% plastic-free materials. Sensors & components Optical heart rate monitor6 3-axis accelerometer + gyroscope Red and infrared sensors for oxygen saturation (SpO2) monitoring7 Device temperature sensor (skin temperature variation available in the Google Health app)8 Vibration motor Band size Textile and polyurethane: One size Wrist size: 130-210 mm around Silicone: Small wrist size: 130-175 mm around Large wrist size: 165-210 mm around Water resistance Water resistant up to 50 meters. After getting the band wet, we recommend drying the band because, as with any wearable device, it’s best for your skin if the band is clean and dry.9 Heart rate6 Like all heart rate tracking technologies, accuracy is affected by physiology, location of device and different movements. Care Give your wrist a rest by taking the band off every now and then. If the band gets wet or you sweat in it, remove and completely dry the band before putting it back on. Dimensions (without band) Length: 1.4 in (34.9 mm) Width: 0.7 in (17 mm) Height: 0.3 in (8.3 mm) Weight 0.01 lb (5.2 g) without band 0.03 lb (12 g) with band Special Edition Stephen Curry Band only Water-resistant coating10