Features: - Classic and reliable heart rate measurement. - High quality heart rate sensor. - Accurate heart rate readings and calories burn. - Suitable for swimming and waterproof up to a depth of 30 meters. - With a battery life of 400 hours, it lasts about one year (when you train one hour per day). - Compatible with iOS and Android mobile devices. - Works with sports and smart watches, gym equipment and many other Bluetooth and ANT+ devices. - Connects with top fitness apps like Strava, MyFitnessPal, Runtastic, Endomondo, Nike+ Run Club, TrainingPeaks in addition to Polar Flow and Polar Beat. Apps list - With Polar Flow, it enables you to: Plan your training, analyze your results and share them with your coach, friends & Polar community. - With Polar Beat, it enables you to: Test your fitness level easily in just 5 minutes without breaking a sweat. - Get motivating feedback immediately after training. - Get an estimate of your running and see how your running performance is developing. - Know exactly how many calories you have burned. Specs: - Battery Type: CR 2025 (Changeable) - Connector size: 34x65x10 mm - Weight: Connector: 21 g Strap: 39 g - Operating temperature: -10 °C to +50 °C - Size : One size changeable from 65-93cm Package Include: - Polar H9 heart rate sensor - Soft Strap - Getting started guide - Information note - Black -