The Ultimate Brake Solution: Complete, 100% Stainless Steel Brake Cylinders. Modern technology and materials have come together to form new parts far superior to originals. Corrosion-contributing cast iron has been totally eliminated. The cylinder casting is solid T304 stainless steel and machined on Computerized Numerical Control (CNC) machinery. The pistons are machined out of stainless steel bar stock to a new design that eliminates excess piston wear should the brake pads wear unevenly and enter and exit the cylinder bore at an angle. These are beautifully made parts.