Brand new GM Chrome proportioning valve Disc Drum brake applications. It performs all the necessary functions when using disc brakes in the front and drum brakes in the rear.This valve will reduce braking pressure to the rear when necessary to prevent the brakes from locking up. It also distributes the brake pressure evenly so that the disc brakes are not doing all the work. This valve will also act as residual pressure the rear drum brakes, allowing better responsiveness when the brakes are applied. It also has a brake warning light switch to alert you if there is any failure in the braking system.This valve is a great upgrade over the original and is a must when upgrading from drum to disc brakes. This is a GM style valve, but will work on almost any Ford, Mopar or Chevy as long as you have the right fittings. This valve is Chromed, making it long lasting and heavy duty.