Bearing kit for 9.6 inch UFP Rotors using UFP Torsion Arms & Vault Hybrid Oil Systems These Torsion arms use a 1.68 inch seal shalft Not the standard 1.71 inch like most other USA trailers This Seal was specificly designed by UFP with special designed lipped area and a tighter fit along with special coating for extra protection. Common Also on 10 inch USA rotors that use the same size Seal shafts of 1.68 inches.