Power Stop K6558-36 Front & Rear Z36 Truck and Tow Brake Kit Precise Machining & Castings - all Power Stop rotors are reverse engineered from OEM samples Beveled Drill Holes help keep rotor temperatures down during extreme braking Up to 180 degrees cooler Rounded Slots keep a clear contact patch between the pad and the rotor by sweeping away gas and dust Silver Zinc Plating - all drilled and slotted rotors (except for hub rotor assemblies) are silver zinc plated to help shield and resist rust during normal operation