The Korky 3 inch Universal Toilet Tank Flapper is adjustable to match your original toilet's performance. It has a universal design and will fit oversized 3 inch 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 inch toilet models including: Kohler, TOTO, American Standard, Gerber and Mansfield.