Featuring a flexible design, the 5051 flapper offers the versatility of fitting both flush valves with or without mounting ears. This flapper comes equipped with an adjustable float to help you regulate how much water is flushed by simply moving the float up or down. The 5051 water-saving toilet flapper is best suited for 1.6 gal/flush toilets. 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.