This is a A-R122850 Seal, Brake Piston O.D. PN: R122850Main Description As Following : A-R122850 Seal, Brake Piston O.D. PN: R122850 Found in Section & Models : Transmission & Rear Axle > Brake Disc and Plates, John Deere TRACTOR: 6140J, John Deere TRACTOR: 6145J, John Deere TRACTOR: 6150J, John Deere TRACTOR: 6150M, John Deere TRACTOR: 6155J, John Deere TRACTOR: 6155M, John Deere TRACTOR: 6800, John Deere TRACTOR: 6810, John Deere TRACTOR: 6820, John Deere TRACTOR: 6830, John Deere TRACTOR: 6830 PREMIUM, John Deere TRACTOR: 6900, John Deere TRACTOR: 6910, John Deere TRACTOR: 6910S, John Deere TRACTOR: 6920, John Deere TRACTOR: 6920S, John Deere TRACTOR: 6930, John Deere TRACTOR: 6930 PREMIUM, John Deere TRACTOR: 7200, John Deere TRACTOR: 7210 Associated Items : A-RE186966, A-R333928 Also A-JD-O-OMR51902, A-JD-S-TM1053 And : Inside Diameter: 12.756" Outside Diameter: 13.098" Width: .125"