This is a A-E81020 Arm, Knife Drive PN: E81020Main Description As Following : A-E81020 Arm, Knife Drive P.N: E81020 New knife drive arm, right. Fits John Deere auger headers.Spline Count: 12 Found in Section & Models : Hay Tool Parts > Disc Mower Parts, John Deere HEAD, CUTTING PLATFORM: 300 (For 31, 36, 61 & 66 Hay Conditioner), John Deere HEAD, CUTTING PLATFORM: 300A (For 31, 36, 61 & 66 Hay Conditioner) Associated Items : New Also This is An Aftermarket Product And : New knife drive arm, right. Fits John Deere auger headers. Spline Count: 12