Fluidmaster has toilet flappers with built-in Microban® protection that actively inhibits bacteria growth that contribute to flapper breakdown Chlorine and hard water resistant, built to last in any water condition The flexible design allows it to fit most 2 in flush valves with or without mounting ears Strong, kink-free metal chain Adjustable float for maximum performance and water savings Comparable to Korky 2004BP PRO series flappers made with Microban® technology are more resistant to premature deterioration than other flappers Microban® additive operates on the cellular level to prevent uncontrolled growth of micro organisms that can damage the flapper Built-in Microban® protection