Ambient light sensor Microphones Speaker NFC Vibration motor Optical heart rate sensor Device temperature sensor (skin temperature variation available through Premium only) Battery & Power Battery life up to 6+ days. Battery life and charge cycles vary with use, settings, and other factors; actual results will vary. Use of the always-on display feature will require more frequent charging. We recommend charging every few days to ensure you're always tracking. Battery type: Lithium-polymer Charge time: (10-80%): Approximately 40 minutes Fast charging: 1 day of battery life in 12 minutes Radio transceiver: Bluetooth® 5.0 Memory Saves 7 days of detailed motion data - minute by minute Saves daily totals for past 30 days Stores heart rate data at 1-second intervals during exercise tracking and at 5-second intervals all other times Water Resistance Water resistant to 50 meters. After swimming or 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. We do not recommend wearing Fitbit Versa 3 in a hot tub or sauna. 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. Materials Versa 3 includes a band made of a flexible material similar to that used in many sports watches, as well as an aluminum watch case. Heart Rate Like all heart rate tracking technologies, accuracy is affected by physiology, location of device and different movements. Environmental Requirements Operating temperature: -4° to 140° F Maximum operating altitude: 28,000 ft Syncing The Fitbit app is compatible with most popular phones and tablets. To set up and use your Fitbit products and services, you must install the Fitbit app on a compatible device running one of the following operating systems: Apple iOS 12.2 or higher. Android OS 7.0 or higher. Syncing range: Up to 30ft Certain features like smartphone notifications may require Android 7.0+. Syncing requires Bluetooth LE and Internet connection. Syncs with Mac OS X 12.2 and up, iPhone 5S and later, iPad 5 gen. and later, Android 7.0 and later. Music control via Bluetooth® Classic on Android and Bluetooth® LE on iOS devices. Band Size Print this guide to find the right size for you. Both small and large sizes included in box. Small - Fits wrist 5.5" - 7.1" in circumference Large - Fits wrist 7.1" - 8.7" in circumference Dimensions 1.59in l x 1.59in w x 0.49inh