Compact-10 Series 8" Dual Diaphragm chrome plated power brake booster. This 8" GM truck brake booster is hand polished before a chrome finish is applied for a top quality finish. The 1-1/8in Bore chrome aluminum master cylinder and proportioning valve is ideal for most disc/drum brake applications. The Compact-10 mounting bracket and push rod assembly is a direct fit to your factory firewall. The Compact-10 series boosters are designed to mount closer to the firewall at a more natural angle than a factory style booster. This type of mount gives you the look and brake performance you want out of your truck. Master Cylinder Bore Size: 1-1/8 in, Bowl Design: Dual Bowl, Master Cylinder Material: Aluminum, Master Cylinder Finish: Chrome, Reservoir Included: Yes, Reservoir Material: Aluminum, Master Cylinder Cap Included: Yes, Proportioning Valve Type: Disc / Drum, Brake Booster Type: Dual Diaphragm, Brake Booster Diameter (in): 8 Booster Material: Steel, Brake Booster Finish: Chrome, Brake Pedal Rod Extension Included: Yes, Mounting Hardware Included: Uses Original, Quantity: Kit.