This is a A-AH215495 Sprocket, Row Unit, 17 Tooth / 80 Chain, Speed Up PN: AH215495Main Description As Following : A-AH215495 Sprocket, Row Unit; 17 Tooth / 80 Chain, Speed Up P.N: AH215495 Dim A (1): 17 ToothDim B (2): 5.912" O.D.Dim C (3): 1.130" Hex Hub Crossed From: AV103736 VAPORMATIC Found in Section & Models : Headers/Platforms/Feeder House > Corn Head Parts, John Deere HEAD, CORN: 1092, John Deere HEAD, CORN: 1290, John Deere HEAD, CORN: 1291, John Deere HEAD, CORN: 1293 Associated Items : New Also This is An Aftermarket Product And : Hub: 1.130" Hex Outside Diameter: 5.912" Teeth: 17