Surge with run time, distance, pace and elevation stats on display. See your routes as you run them, then scroll through workout summaries and split charts to stay on track whilst you train. With continuous heart rate readings, Surge keeps you in the zone - all day and during workouts. No straps. No clips. No guessing. To download your size guide, simply open and save the PDF to your PC and follow the instructions on the document. Quantified sleep. Quality data. So you can make the most of your day by making the most out of your night; Model: fitbit surge. Size: small. Tracks steps, distance, calories, heart rate and sleep. Call notifications with caller ID, text notifications, email notifications, . Compatible with syncs with windows vista and later, mac os x 10.6 and up, iPhone 4s and later, iPad 3 gen. And later, and leading android and windows devices. Connects via Bluetooth. Water resistant up to 5m. 168 hours battery life from a 2 hour charge. LCD screen. Size H20, W9.8, D7cm. Weight 35g.