This is a A-10001-1013 Slip Sleeve Yoke, 1 1/4" Round Bore, 5/16" Keyway PN: 10001-1013Main Description As Following : A-10001-1013 Slip Sleeve Yoke, 1 1/4" Round Bore, 5/16" Keyway PN: 10001-1013 Found in Section & Models : Driveline > Driveline Components, Neapco DOMESTIC: 1000 SERIES, Driveline > Yokes, Neapco DOMESTIC: 1000 SERIES Associated Items : New Also This is An Aftermarket Product And : Weasler alternative to original part. Bore: 1 1/4" Rd. Centerline: 5 1/2" Keyway: 5/16"