PROS3KP15 Fluidmaster Pro Series Flush Valve Seals for Kohler and American Standard The Fluidmsater PROS3K Pro Series Kohler and American Standard Flush Valve Seals 3-Pack. Designed to specifically fit Kohler AquaPiston flush valves and American Standard Champion 3 flush valves. Built from durable silicone and made to last.Prevent or stop leaks from specialty flush valves with this 3-packFits: Kohler AquaPiston and American Standard Champion 3Easy to installDurable silicone seals - last 10x longer than standard materialChlorine and hard water resistant5 year warranty