Black line rotors use premium casting to provide the ultimate performance rotor. With Molybdenum, Chromium and a high carbon content, they offer increased hardness and temperature stability. The result is a rotor that is well suited to the abrasive nature of racing brake pads and those found on European sports cars. Excellent wear resistance and stopping power make these ideal for high performance racing applications as well as sports and performance cars. These performance rotors are E-coated in black and a thermochromic paint is applied to the rotor edge. The thermochromic paint allows you to match your brake pad temperature range with actual rotor temperatures.