This Corbelle® toilet tank features innovative AquaPiston technology, a patented flush engine that delivers a fast, powerful and virtually plug-free flush. A 1.28 gal flush provides significant water savings of up to 16500 galper year, compared to a 3.5 gal toilet, without sacrificing performance. Pair this tank with the K-4144 bowl for a complete Corbelle® skirted toilet. Kohler® Toilet Tank, Corbelle®, 1.28 gpf, Left Hand Lever Flush, Vitreous China, Dune