The Korky 2X Long-Life Toilet Flush Valve Seal Fits Kohler Toilets is designed to replace the original seals on Kohler AquaPiston, Class Five, and Class Six toilets. Replace original Kohler Seal: GP1059291. The proprietary Chlorazone II rubber formulation lasts 2 times longer than other seals to hold up in the harshest environments. Easy to install, the Korky 451 includes (1) 2X Toilet Flush Valve Seal that fits Kohler.