Here is a simple and cost efficient way to operate your stock mechanical speedometer with an electronic automatic transmission equipped with a vehicle speed sensor. The Cable X speedometer adapter is designed to pick up the electronic speedometer signal and will operate the cable driven speedometer to the corresponding speed. Encased in a metal, 4.75" x 3.5" x 2.25" box, the Cable X can be mounted under the dash or on the firewall. A snap to install, just three wires - hot, ground and signal. Designed for use on 1953-1968 Corvettes with a screw on cable to the speedometer.