This is a A-RBX1 X Hub PN: RBX1Main Description As Following : A-RBX1 X Hub P.N: RBX1 Dim A (1): 2"Dim B (2): 2-1/2"Dim C (3): 7/16"Dim D (4): 1"Bore: 1" roundKeyway: 1/4" X 1/8" Replaces: PM20030016 SPROCKET/HUB/PULLEY/IDLER , 20030016 EDCOR , Crossed From: WSH30016 , , W20030016DS CASE-IH , 3016-0128 , , 6713-58713 JOHN DAY , 673-S80031100 , , 673S80031100 , 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" round Keyway: 1/4" X 1/8"