This top-rated toilet flapper prevents leaks and saves precious water. This is an adjustable toilet flapper that fits 1.6, 3.5, 5, and 7 gallon toilets and saves up to 2.5 gallons per flush (GPF) when installed in an old 5 to 7 GPF toilet. It stops existing leaks and prevents new leaks for 5 years. The end cap allows you to adjust the flush to your needs and the toilet's capabilities. Soft and flexible, it installs easily in seconds without tools. This product is very affordable for the big job it has to do. Approximately 3 1/4" in diameter.