SP Performance® Cross Drilled Brake Rotors with Black ZRC Coating have a design that offers the best possible cooling and venting of brake pad gasses, brake dust and moisture. Unlike SP Performance competition there is no sharp edge on SP Performance chamfer. This is accomplished by the use of an outer radius curve rather than a countersink. With the radial curve, it virtually eliminates an edge on the surface of the hole. This smooth surface also makes the rotor more pad friendly by reducing the wear of the pad caused by the friction scraping against a sharp edge. SP Performance Black ZRC coating provides the the rotor with the most durabale and longest lasting coating on the market. The coating is designed to fully cure with the heat created during the bedding in process of the rotors. Disclaimer: Coating will wear off the rotor where the brake pads make contact.