The korky ultra high performance flapper is the most universal 2 in toilet flapper available. The toilet flapper valve adjusts to match original toilet settings and eliminates water waste by decreasing the amount of water flushed. Ideal for all standard 2 in toilets, including 1.28, 1.6, 3.5 and 5 gal per flush (gpf). The exclusive longest lasting red rubber resists chlorine, bacteria, city water treatment, hard water and well water. Recommended by the Clorox help line, this Korky toilet flapper valve is proven longest lasting.