This Cylinder Kit contains Pistons made of hypereutectic aluminum alloy, which makes the piston inherently stronger. It is also more resistant to expansion and contraction, as well as scuff and corrosion resistant. Efficiency improves due to a better seal between the rings and cylinder wall.Includes: (1) HCTAR51741 Piston & Rings (1) HCTAR54552HC Piston (1) HCTR40615 Cylinder Liner (1) HCTAR65507 Cylinder Liner O-Ring Kit The HCTAR63272HC High Compression Cylinder Kit fits equipment brands such as: John Deere