Polar Speed Sensor Kit S-Series
The Polar Speed Sensor is compatible with the Polar S510, S520, S625X, S710 and S720i Heart Rate Monitors. The Polar Speed Sensor is a wireless sensor measuring cycling speed and distance via a magnet rotating on the front or the rear wheel depending on the sensor. The Polar Speed Sensor is shipped with a Polar Bike Mount.
Merchant: Randall Scott Cycle Company