2.22" ID; Performance Machine Classic 1 Piece Stainless Steel Brake Rotors are CNC precision machined to ensure a flat and parallel surface. The 420 stainless steel disc is hardened to meet RC36 specifications yielding a rotor with a higher resistance to deformation. Increasing the hardness and strength of the material allows for the machining of a lightweight 5-spoke design for improved braking performance. The braking surface features a drilled sweep pattern for optimal heat dissipation. PM Classic 1 Piece Stainless Steel Brake Rotors are designed for use with OEM and most aftermarket wheels and calipers. •CNC precision machined. •Lightweight 5-spoke design. •420 Stainless Steel - Material thickness: 0.200".