Isolation mounts are used to attach and position systems, accommodate displacement, and isolate components from the surrounding structure (vibration, shock, noise.) Mount Type: Two-Piece - Symmetric Head Outside Diameter (mm): 98.6 Head Outside Diameter (in): 3.88 Head Thickness (mm): 36.6 Head Thickness (in): 1.44 Pilot Outside Diameter (mm): 56.9 Pilot Outside Diameter (in): 2.24 Inside Diameter (in): 0.80, 0.8 Inside Diameter (mm): 20.2 Mount Height (mm): 45.2 Mount Height (in): 1.78 Bonded Sleeve: No Standard Bolt Size: .75"