This is a A-101-5520 Safety Slide Lock Tractor Yoke PN: 101-5520Main Description As Following : A-101-5520 Safety Slide Lock Tractor Yoke PN: 101-5520 Found in Section & Models : Driveline > Yokes, Weasler Domestic: 55 Series Associated Items : A-13004020 Also This is An Aftermarket Product And : 55 Series Safety Slide Lock Tractor Yoke. 1-3/4" 20 Spline Yoke. Original Weasler part. Bore: 1 3/4" - 20 Spl.