Check the listing for details. 7 " Dual Booster Power Master Cylinder &Bottom Disc/Disc Proportioning Valve Kit. Condition: New. Listed at 157.65 USD. 7 " Dual Booster Power Master Cylinder &Bottom Disc/Disc Proportioning Valve Kit Product Description:Black 7" Dual Diaphragm Power Brake Booster and a new Cast Iron Dual Bail Top Master Cylinder for universal applications.This GM Corvette master cylinder has 4 ports and is the Bail Top Style & has a 1" Bore(9/16" & 1/2" Ports on each side).Mounting holes measure 3 3/8" center to center.Universal booster will bolt up to most street rods, hot rods, and other vehicles with no problem.The Dual Booster Adds 30% MORE Stopping Power.GM Disc Disc Bottom Mount Brass Proportioning Valve Kit. Package:Black 7" Dual Diaphragm Brake Booster Black 1" Bore Cast Iron Dual Bail Top Master CylinderBottom Mount Proportioning Valve Kit Professional Installation is Highly Recommended. (No Instruction Included)