Make the most out of every training session with the Polar H7 Bluetooth Smart Heart Rate Sensor. It provides real-time heart rate to compatible mobile training apps, including Polar Beat and Polar Flow, via low energy Bluetooth Smart technology. Also connects with the majority of Polar heart rate monitors on the market and compatible gym equipment. Includes a soft fabric chest strap size M-XXL (30-45 Inch) that seamlessly adapts to your body shape. User replaceable battery. Includes limited two-year manufacturer"s warranty.