The CI Drive is the ultimate solution for effortlessly upgrading your cable-driven mechanical speedometer. Supporting GPS and modern transmission signals, it's the simplest and most versatile speedometer conversion for any vehicle. Requiring only 12 volts and ground, it's a hassle-free plug-n-play solution that eliminates the need for tedious calibration or subscription services. The CI Drive is designed to operate a cable-driven speedometer using an electric speed signal from GPS, Transmission or ECM. With a Drive Output Thread of 7/8"-18 and a Square of 0.112", the CI Drive offers flexibility, and its calibration range from 170-1650 turns per mile ensures precision for diverse speedometers. With its versatile design, the box can be efficiently installed either in the dashboard or under the hood. Default calibrated for US speedometers at 1000 turns per mile, it adapts effortlessly to signals from GPS or VSS (Vehicle Speed Sensor), automatically calibrating with the included GPS antenna.