Piston Ring Set Piston Ring Sizes: 1st Ring: 2.5MM (Taper) 2nd Rings: 2MM Oil Rings : 5MM (Chrome) Condition: - Aftermarket Replaces part numbers: 6678075, 6655178 We have Many other tractor parts available! Specializing in parts for engines, hydraulics, driveline and electrical since 1995.