This is a A-800-8310 Round Bore Implement Yoke (With Keyway & Set Screw) PN: 800-8310Main Description As Following : A-800-8310 Round Bore Implement Yoke (With Keyway & Set Screw) PN: 800-8310 Found in Section & Models : Driveline > Driveline Components, Bondioli & Pavesi 100 Series: Size 3, Walterscheid W Series: I, Driveline > Yokes, Bondioli & Pavesi 100 Series: Size 3, Walterscheid W Series: I Associated Items : New Also This is An Aftermarket Product And : Weasler alternative to original part. Bore: 1 1/4" - 31.75 mm Standard Keyway: 1/4" - 6.35 mm