The name of the game in racing is traction, and keeping your tires firmly planted under all track conditions and surface abnormalities have become a science. Monitoring suspension deflection through shock absorber movement is the common method of tracking suspension and tire performance. Racepak users can employ these shock absorber travel sensors to monitor even the slightest amount of shock travel or tire shake. Shock travel graphs will provide you with the data you'll need to tune 'to the track' more precisely.The rear shock travel sensor kit contains two 8' linear shock travel sensors, two signal conditioning modules and an analog extension cable.