2x Rear Disc Brake Rotors – 31507. Rotors Material: Steel. Brake Rotor. Position: Rear. Installed on a vehicle for which it was not designed to;. Warranty policy does Not apply to any part that has been: Altered, misused, or improperly-installed; Installed on a vehicle for which it was not designed to; Installed on a racing or high-performance vehicle, or vehicle with modified suspension/rims/tires.