DESC: Polar Power Output Sensor W.I.N.D. Provides valuable cycling data like power output, cycling efficiency, pedaling index and L/R balance. The data is wirelessly transferred to Polar CS600 cycling computer. Provides valuable cycling data like power output, cycling efficiency, pedaling index and L/R balance. Can be purchased as an optional accessory or as a complete set with the Polar CS600 with Power cycling computer. With 2.4 GHz disturbance free transmission. Requires CS600 (sold separately) Also available as a combo with Power Output: CS600/Power saves money as a combo