Fit for Kohler GP1059291 replacement seal is made of outstanding silicone materials, which are superior to rubber; designed to meet various water challenges; offers excellent and long-lasting performance; ensure reliable seal for kohler flush valve K-GP1059291 is the perfect replacement for Kohler cartridge flush valve seals and fits all Kohler toilets with cartridge flush valves. The flush valve seal is made of silicone. Compared with ordinary rubber, it is more resistant to chlorine and other substances in the water. It is not easy to deform and is less likely to produce bubbles, making it more long-lasting. Easy Installation,Simply turn the valve stem to remove it, then take out the old gasket at the bottom of the valve stem. Replace it with a new seal ring, and then screw the valve stem back on. K-GP1059291 flush valve seal outer diameter 3.3 inches, inner diameter 2.6 inches