The Polar H10 heart rate sensor is accurate and comfortable with ultimate accuracy. Compatible with Go Pro Hero 4 &5, view your heart rate on your Go Pro recordings. Also compatible with Polar Beat, gym equipment and 3rd party apps. The H10 has an hour�s worth of memory to record data without the need of a wrist unit. The new Pro Chest Strap has one extra electrode to prevent interference. The Polar H10 is fully water resistant and transfers heart rate data in water with 5 kHz transmission. Works with gym equipment and Polar Club/Team app. The Polar H10 works with all Polar watches and trackers that use Bluetooth to transfer data and Polar has built-in memory for heart rate data from one training session direct to your phone after training.