The Fluidmaster 2602 Sealant Ring is specifically built to fit Fluidmaster's 555C Flush Valve Repair Kit. Offering a simple solution for problem toilet flush valve and tank to bowl leaks. Built to restore you toilet flush valve performance by sealing leaks, without having to purchase a new toilet flush valve. Durable featuring quality rubber build and strong sealant for a long lifespan with a 1 year warranty. Use to replace and repair corroded flush valve seats.