Best for older toilets; 3.5 GPF or more (before 1994). The Fluidmaster® 500 universal 2 in toilet flapper features a solid frame design; to resist bending; or twisting and secure the best seal with every flush. Eliminate having to jiggle the toilet handle with this universal design that fits most 2 in flush valve toilets. Includes a 1 year warranty and built-in Microban® technology. 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. Upgrade your old toilet flapper to a high-quality replacement; the Fluidmaster® universal toilet flapper."