1974-1986 Jeep CJ Aluminum Master Cylinder, Black 7" Booster and Proportioning Valve. Master cylinder is an aluminum Corvette style and is designed for use with disc/disc or disc/drum brakes. Booster is chrome 7 inch dual diaphragm which offers better stopping than single diaphragm boosters. Kit also includes proportioning valve with mounting bracket and stainless brake lines. 8" booster and chrome options available. This complete kit is designed to bolt up to 74-86 CJ Jeeps.