Motivation is your best accessory with Fitbit Alta; ; a customisable fitness tracker designed to fit your personal style. Stay motivated by tracking all-day activity ; steps, distance, calories burned and active minutes ; and get credit for workouts with SmartTrack automatic exercise recognition. At night, track your sleep and set a silent alarm to get your best rest. To download your size guide, simply open and save the PDF to your PC and follow the instructions on the document; See stats and time with a bright oled tap display. Model: fitbit alta. Size: small. Tracks steps, distance, calories and sleep. Call notifications with caller ID, text notifications, email notifications, calendar alerts. Compatible with syncs with mac os x 10.6 and up, iPhone 4s and later, iPad 3 gen. And later, android 4.4 and later, and windows 10 devices. Connects via Bluetooth. 120 hours battery life from a 2 hour charge. LED screen. Size H3.3, W22.3, D10.1cm. Weight 25g.