The Polar H10 Bluetooth Heart Rate Sensor is the first choice for accurate heart rate monitoring. Connect it with 2 Bluetooth training devices simultaneously. Compatible with Polar Beat so you can train with your phone or use the inbuilt memory to train without your phone and transfer the data later! Suitable for swimming with 5kHz transmission and silicone dots to keep your strap in place every stroke. Now available with ANT+ to expand your communication with other devices!