Replacement rear brake rotor, 5/130 Porsche and 5 / 4.75in Chevy short spline. Works for both swing axle and I.R.S. (I.R.S. requires P/N 22-5281-7 spacer). Double drilled for use with either Porsche 5 x 130 bolt pattern using M14-1.5 threads or Chevy 5 x 4.75 bolt pattern using 12mm threads. Must purchase studs separately. 11in overall diameter, 3-1/2in depth. All bearing races must be pressed into rotors.