Engineered with Heat-Flowed cast iron to give our wheel cylinders the ideal balance between tensile strength and hardness, Anodized coating provides complete 360º protection against rust, moisture and oxidation, Reinforced pistons (FeSi) feature higher tolerance to pressure and increased wear resistance, PCRVi (Pressure Conscious Reducing Valve integrated) reduces pressure buildup, Trivalent-coated bleeder screws provide extra protection and added durability, Premium ProSeal™ Nitrile Rubber (NBR) cups and boots for long lasting performance, Wheel cylinder bores are surface tested to ensure an optimum sealing surface for the pressure cups, Part Reference Numbers : W610144 451 420 00 18 WC370222, Kit Includes: 2x Rear Drum Brake Wheel Cylinder (Both Side)