Hypertech's In-Line Speedometer Calibrator Modules are an in-line module that corrects your vehicles speedometer and odometer for unlimited tires sizes and/or rear gear ratios. These modules are perfect for vehicles with computers that don't allow for tire size and/or rear gear ratio correction or want to re-calibrate for sizes outside the range of programmers. Installation is a snap. Using the included USB cable, connect the Hypertech In-Line Speedometer Calibrator Module to your PC and enter the new tire height and/or rear gear ratio. There are no limitations to tire height or rear gear ratios. Next, simply disconnect the factory connector to the instrument cluster (behind the dash), snap in the Speedometer Calibrator Module, reconnect the cluster, and you¹re done! In a matter of minutes, you can accurately correct your speedometer and odometer readings (as required by law).