SpeedoDRD Y1 Speedometer Calibrator The smallest electronic speedometer/odometer calibration device in the world. Saves max speed, which can be recalled to your stock speedometer gauge. Widest calibration range on the market (ratio based and multiplier/divider capability). Built in testing mode to ensure proper installation Easier to setup than any other device on the market. Simple plug-in installation for many vehicles using factory OEM connectors. Works for any 3 wire Hall Effect Sensor, or 2 wire Ground Switch Sensors. Works for vehicles which display MPH or KPH Ability to convert MPH to KPH, or KPH to MPH. Ratio based correction in 0.1% steps, up to 99.9% + or -. Fractional frequency multiplier & divider with 0.1 steps, up to 99.9 + or -. 18" wiring harness (1.5ft) Weather proof design to protect against the elements. All SpeedoDRD units being shipped are now firmware version 3M, with built in fractional frequency multiplier and divider, in addition to the ratio based frequency adjuster. The multiplier / divider is a special application feature that allows users to do complete gauge cluster or transmission swaps with vehicles that have completely different PPM (pulse per mile) rates, no other calibration device has a wider frequency adjustment range. Made in the USA. 3 year product replacement warranty