Put the finishing touch on your lifted vehicle with Rough Country's Speedometer Calibration Device! This easy-to-use Speedometer Calibrator helps you quickly and easily reprogram your vehicle's speedometer to match the output of your larger tires.Your vehicle's computer is designed to track the speed based on your stock tire height. When upgrading to larger tires, there will be a discrepancy between your actual speed and the readout on your speedometer.This plug and play device connects directly to your vehicle's Diagnostic Link Connector Port and in just a few short minutes your speedometer reads true again! Rough Country's Speedometer Calibration Devices don't just simply change your in-dash readout, they update your vehicle's ECM, ensuring accurate shift points and proper electronic stability control.Finally, you can get an affordable and accurate speedometer calibration with an easy and intuitive setup process! This device can also easily read and check all diagnostic codes to help you manage â