The Fluidmaster replacement flush valve seal for Mansfield #210 and# 211 Toilets is a quick and easy way to eliminate leaks on your specialty flush valve toilet. Designed to be a direct oem replacement for a perfect fit and secure seal. Built to last, this silicone seal lasts up to 10x longer than standard models and is chlorine and hard water resistant. Eliminate water waste and get a part made to fit secure, with the Fluidmaster 510M-001-P10 Mansfield specialty flush valve seal replacement.More resistant to heat and chemicals,Durable and flexibility,Ensures efficient and complete flushing