Changes affect your speedometer. These units will handle nearly all of your signal conversion and calibration issues after changing rear end gears, tire sizes, or drivetrain changes. They can recalibrate 2K pulses per mile (ppm) through 250K pulses per mile speedometer pulse rates. Plus, these units provide greater flexibility by allowing multiplication up to 16 times, taking an 8,000 ppm signal and converting to a 128,000ppm output. They include a regulated 5V sensor output and the push-in terminals have been replaced by screw-in terminals. They feature built-in LED displays and pushbutton switches to simplify setup and calibration. Modifications to your vehicle may mean adjusting your speedometer for accuracy.