Transform Your Wilwood Disc Brake Upgrade with this new 25mm Master Cylinder. Its 25mm Bore Means More Brake Fluid, More Pressure to All 4 Corners, and Superior Stopping Power with a Firm Pedal Feel. Plus, Dual Circuits Provide Extra Security. (Reservoir NOT Included) Choose the EMPI Brake Fluid Reservoir 17-2878-0 for Top-of-the-Line Installation.