Air compressors provide air supply to different parts of the engine where needed Mount Type: Mushroom Mount Overall Length (mm): 60.5 Overall Length (in): 2.38 Sleeve Length (mm): 41.4 Sleeve Length (in): 1.63 Head Outside Diameter (mm): 71.1 Head Outside Diameter (in): 2.8 Pilot Outside Diameter (mm): 41.1 Pilot Outside Diameter (in): 1.62 Inside Diameter (mm): 19.6 Inside Diameter (in): 0.77 Standard Bolt Size: M16