Scosche's Rhythm+ Armband Heart Rate Monitor fits discreetly around your lower arm and connects to your devices via both Bluetooth and Ant+, working with over 200 Applications including Strava and MapMyFitness.__ACCURACY OF SENSORS_ The Rhythm+ employs PerformTek Precision Biometrics* which is sensor technology that continuously measures real-time biometric data to give highly accurate monitoring and measurement. __ Use your favourite fitness app on your smartphone or tablet to monitor your heart rate, calories burned, distance, speed, pace and more. Rhythm+ optically measures blood flow and body movement to ensure the most accurate data possible.__100 FT. RANGE_ It means you can be away from your device like when you are using your Turbo trainer and it still works the same.__8 HOUR BATTERY LIFE_ A generous battery allowance will keep you working for up to 8 hours continuously, then simply plug it in with the charging cable (included) to recharge the Rhythm+ for your next use.__IP67 Waterproof construction: Submersible up to 1 metreBreathable lightweight armband: No chest strap requiredHyper-Accurate: Patented optical sensor technologyApp Friendly: Works with hundreds of appsBluetooth Smart & ANT+: Works with virtually any device100ft. Range: Workout up to 100ft. away from your device8 Hour Battery Life: Internal rechargeable batteryGreen/Yellow Optical Sensors: Superior measurements compared to only green sensorsRhythm+ works with most popular health and fitness apps, including:_ DigiFit_ Runkeeper_ MapMyFitness_ Strava_ and more__*Valencell's PerformTek biometric sensor technology is the only continuous heart rate monitoring technology proven via extensive testing to be accurate during virtually any exercise and in virtually any environment to give people meaningful fitness assessments.__