This is a A-R43531 Shaft, PTO (1000 RPM) PN: R43531Main Description As Following : A-R43531 Shaft, PTO (1000 RPM) P.N: R43531 Dim A (1): 60.00" LongDim B (2): 21/21 Spline Crossed From: WN-R43531 , , WNR43531 , Found in Section & Models : PTO Parts > PTO and Related Parts, John Deere TRACTOR: 4520 (W/ Syncro-Range Transmission) Associated Items : New Also A-JD-O-OMR46935, A-SMJD203 And : Length: 60.00" Spline: 21 / 21