SP Performance® Diamond Slotted Brake Rotors with Gray ZRC Coating were designed to maximize the out-gassing while maintaining the structural integrity of the rotor. The series of slots and diamond "wipes" the surface of the pad clean, and vent expanding gases which would cause brake fade at higher temperatures. The slots also greatly improve wet weather braking by preventing hydroplaning between the pad and rotor. Diamond slotted rotors are a unique design in slotted technology that offers style, performance and reliability. SP Performance Gray 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.