Fitbit Alta HR

Get the power of continuous heart rate in Fitbit's slimmest design yet-all day, during workouts and beyond. Alta HR contains a Bluetooth 4.0 radio transceiver. The operating temperature is minus 10 to 45 degree Celsius. With heart rate, you can better measure calorie burn, and use zones (Fat Burn, Cardio, and Peak) to find the right workout intensity for your goals. With sleep stages powered by PurePulse heart rate, automatically track your time spent in light, deep and REM sleep and take steps toward a better night's rest. See how working out more can improve your health by comparing your resting heart rate trends to your activity. Sync stats wirelessly & automatically to computers and 200+ leading iOS, Android and Windows devices. Automatically track your steps, distance, calories burned and active minutes with up to 7 days of battery life. Tap to see your stats, time & notifications on an OLED display, plus customize your clock face. Maximum operating altitude: 30,000 feet. Made of a flexible, durable elastomer material. The minimum and maximum circumference range between 170 - 206 millimeters. Buy with confidence when your Fitbit product 'ships from and is sold by' the following authorized Fitbit retailers: Amazon.com, Heart Rate Monitors USA and Clever Training. Fitbit does not guarantee the quality or authenticity of products purchased from non-authorized resellers on Amazon, and they are not eligible for warranty and replacement from Fitbit.