Fluidmaster's 504 long-lasting toilet flapper is designed to withstand harsh water conditions. Featuring chlorine-resistant material and built-in microban to extend lifespan. Only Fluidmaster has toilet flappers with built-in microban protection. Not just simply a coating, microban is specially built into the construction of our flappers to fight flapper breakdown and combat bacteria. This versatile flexible frame design fits flush valves with or without mounting ears and works with most 2" brass and plastic flush valves. Quickly eliminate water waste due to a faulty flapper with Fluidmaster's 504 universal chlorine-resistant long-lasting toilet flapper.