Rotary vane compressors each have four self-wearing carbon vanes, when the vanes become worn to a certain point you will notice a large reduction in air flow. This listing is for a brand NEW replacement set of vanes for the Gast 0323 and 0523 pumps as well as the RV33 used on 0323/0523 RV33 oil-less "Q" models with internal filtration. High-quality, long-lasting vanes for Gast 0323 / 0523 series oil less rotary vane vacuum pumps. Sold in a set of 4, These are an aftermarket direct replacement for Gast vane part number AH850A. Item Length (In):1.3 Item Width (In):.1 Item Height (In):1.4 Item Length (mm):32 Item Width (mm):3 Item Height (mm):35 Service kit returns your unit to original factory performance specifications. Recommend for service every 2 years. Important: Use Gast AH225D flushing solvent to flush debris from pump when servicing unit (not included) Service kit includes: (4) AH850A Vanes ONLY. Does NOT include any other parts or pieces. Fits 0323 and 0523 units including 0323-101Q-SG588DX, 0523-101Q-SG588DX, 0523-V184T-SG588DX and 0523-V191Q-G588DX models.