These Wilwood steel rotors are designed with a special high-strength steel alloy and a processing technique that provide greater strength, stability, and resistance to warping. They're great for use on lightweight formula, open wheel, dirt track, and drag race cars because they don't require continuous thermal cycling or cooling periods. Their lightweight design greatly reduces rotating mass and unsprung weight. Each rotor is ground for flatness and is plated with a protective coating. They're available in both solid and cross-drilled designs.