The CPS Products TR21X2 is a Complete Rebuild Kit for the TR21 Recovery Machine. This kit includes a Compressor Head (TR21X4), Pistons, Bearings, Eccentrics, Cylinders, O-rings and Bolts. The Oil-less Compressor Head Assembly includes valves and pressure switch assembled ready to install. This kit is compatible with the TRS21 Recovery Pump and TRS600 Recovery Pump.