Wear your heart on your sleeve. The Polar OH1 Optical Heart Rate Sensor and Arm StrapWorks for any sport to provide real-time feedback for optimal training. Providing versatility, comfort and simplicity, the Polar OH1 is an optical heart rate sensor worn on the arm. Whether running, riding or rocking a workout at the gym, this heart rate monitor armband accurately and consistently captures heart rate using Polar’s proprietary algorithm and 6-LED solution. Build the heart of a champion with Polar.