Heart Rate Monitors and GPS Watches Cyprus / Polar - Introducing Polar OH1 optical heart rate sensor. Optimized for use on the lower or upper arm, Polar OH1 provides an alternative method
Amazon.com : Polar Verity Sense - Optical Heart Rate Monitor Armband for Sport - ANT+ and Dual Bluetooth HRM - Waterproof HR Sensor with only One Button - Compatible with Peloton, Zwift
Amazon.com : Polar Verity Sense - Optical Heart Rate Monitor Armband for Sport - ANT+ and Dual Bluetooth HRM - Waterproof HR Sensor with only One Button - Compatible with Peloton, Zwift