The Fluidmaster 503 Universal Toilet Flapper is designed to be a quick and effective replacement toilet flapper. With a flexible design, this flapper can be used on flush valves with or without mounting ears and fits most 2" brass or plastic flush valves. Quickly replace old problem flappers with this universal design. The included kink-free metal chain eliminates flapper hang up, while the built-in microban extends flapper usage. Only Fluidmaster has toilet flappers with built-in microban protection. Not just simply a coating, microban is specifically built into the construction of our flappers to fight flapper breakdown and combat bacteria. The Fluidmaster 503 2" flapper, a flexible design for your toilet.