This is brand new unused aftermarket Ingersoll Rand Model 231 Type 30 Major Overhaul Kit . This kit contains aluminum connecting rods, bearings, Crankpin bush, Valve, Rings Gaskets. This is not a Ingersoll Rand parts but it is compatible with IR Air Compressors. This is a Private-label parts. Following are the compatible parts number with Air compressor Parts number: -Gasket Kit Part -Valve/Head Rebuild Kit Part -Ring/Gasket Kit Part -L.P. Piston Ring Kit Part -H.P. Piston Ring Kit Part -Bearing/Rod Kit Part