The Korky 3 in universal toilet tank flapper is adjustable to match your original toilet's performance. It has a universal design and will fit oversized 3 in flush valves found in newer 1.6 and 1.28 gpf toilets since the year 2005. The exclusive longest-lasting red rubber resists chlorine, bacteria, city water treatment, hard water and well water. The adjustable toilet tank flapper has multiple settings to ensure it fits popular 3 in toilet models including Kohler, TOTO, American Standard, Gerber and Mansfield. Made of flexible rubber for a tight seal and easy-to-install.