Used tachometer resistance wire for all 1971-73 Mercury Cougar XR7's and those that wish to add a factory tachometer to your standard instrument cluster. This wiring segment was removed from the main under dash harness of a 1971-73 Mercury Cougar XR7. No wires to splice. This wiring segment includes the plug to the tachometer, lead to the fuse block, and to pins, one goes to the ignition switch, the other goes to the 'thru the firewalll plug'.