This is a A-RBX1-38 X Hub PN: RBX1-38Main Description As Following : A-RBX1-38 X Hub P.N: RBX1-38 Dim A (1): 2"Dim B (2): 2-1/2"Dim C (3): 7/16"Dim D (4): 1"Bore: 1-3/8" roundKeyway: 5/16" X 5/32" Crossed From: WSH30022 , , 3016-0134 , , 6713-59113 JOHN DAY , 673-S80031700 , , 673S80031700 , Found in Section & Models : Chains/ Sprockets/ Pulleys/ Hubs > Hubs, (Miscellaneous) (UNDEFINED): SEVERAL Associated Items : New Also This is An Aftermarket Product And : Dim A (1): 2" Dim B (2): 2-1/2" Dim C (3): 7/16" Dim D (4): 1" Bore: 1-3/8" round Keyway: 5/16" X 5/32"