An ideal accessory for cycling enthusiasts, the Polar CS Series wireless speed sensor measures cycling speed and distance via a magnet rotating on the front or rear wheel. Then, once you've completed your workout, you can download the information to one of Polar's CS Series cycling computers for further analysis or goal development. The data, which includes current, average, and maximum speeds along with total distance completed, helps you make the most of your high spin workouts. The sensor is shipped with a Polar bike mount for easy installation and is backed by a two year warranty. Note that the sensor is compatible only with CS Series cycling computers, such as the CS100, CS200, or CS300. Owners of S Series computers will need to purchase a different sensor.