This is a A-RBW1 W Hub PN: RBW1Main Description As Following : A-RBW1 W Hub P.N: RBW1 Dim A (1): 1-5/8"Dim B (2): 1-13/16"Dim C (3): 7/16"Dim D (4): 1"Bore: 1" roundKeyway: 1/4" X 1/8" Crossed From: WSH20016 , , 20020016 , , 20020016 , , 3016-0115 , , 6713-57713 JOHN DAY , 673-S80021100 , , 673S80021100 , Found in Section & Models : Chains/ Sprockets/ Pulleys/ Hubs > Hubs, (Miscellaneous) (UNDEFINED): SEVERAL Associated Items : New Also This is An Aftermarket Product And : High Quality Afternaket Shipped from Both US and Canada