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