This is a A-104-5521 Ball Shear Clutch, 55 Series, 1 3/8" X 21 Spline, 27,800 in/lb Setting, w/ Safety Slide Lock PN: 104-5521Main Description As Following : A-104-5521 Ball Shear Clutch, 55 Series, 1 3/8" X 21 Spline, 27,800 in/lb Setting, w/ Safety Slide Lock PN: 104-5521 Found in Section & Models : Driveline > Clutch, Weasler Domestic: 55 Series Associated Items : A-13004000 Also This is An Aftermarket Product And : Original Weasler part. Bore: 1 3/8" - 21 Spl. Shear Bolt: (2) 3/8" x 16 Gr. 7