This 4 pack of FlushLine toilet flappers for Kohler Class 5 GP1016546 and GP1042313 toilet is a perfect fix to your flushing issues. This 3" flapper pack also fits Kohler's Bancroft 3487 and 4633, Cimarron 3496, 3497, 3499, 4634, 11465, and 11466. These heavy-duty flappers are easy to install, and include stainless steel D-Chain and loop hooks to eliminate chain fall-off. These flappers are a large bulb design, which fits toilets that are 2 pieces, made since 2005. FlushLine's flappers are made of state-of-the-art Dura-Chlor. Dura-Chlor is a chemical resistant, code compliant material that provides the highest quality and ensures a consistent seal every single flush. It is resistant to chlorine and hard water. Each FlushLine flapper comes in a specially engineered box that ensures the integrity of each flapper's shape. FlushLine flappers are made in the USA. Why FlushLine Flappers? Traditional toilet flappers are made of rubber and can deteriorate over time. This is caused impart to the toilet bowl cleaners you drop into the tank or by chemicals used by utilities. Over time rubber flappers will deteriorate thus causing your toilet to leak. FlushLine's flappers, however, are made of chemical resistant Dura-Chlor. Dura-Chlor is a chlorine resistant, code compliant material that provides maximum trouble-free performance to your toilet. Each Flushline flapper is made with pride in the USA. Replace or fix your toilet flapper with a FlushLine toilet flapper.