This is a A-100-1221 Spring-Lok Tractor Yoke PN: 100-1221Main Description As Following : A-100-1221 Spring-Lok Tractor Yoke PN: 100-1221 Found in Section & Models : Driveline > Driveline Components, Weasler Domestic: 12 Series, Driveline > Yokes, Weasler Domestic: 12 Series Associated Items : A-13003100 Also This is An Aftermarket Product And : 12 Series Spring-Lok Tractor Yoke. 1-3/8" 21 Spline. Original Weasler part. Bore: 1 3/8" - 21 Spl.