This Irvine™ toilet tank features innovative AquaPiston® technology, a patented flush engine that delivers a fast, powerful and virtually plug-free flush. A 1.28-gallon flush provides significant water savings of up to 16,500 gallons per year, compared to a 3.5-gallon toilet, without sacrificing performance. Pair this tank with the K-20148 bowl for a complete Irvine ™ skirted toilet. 1.28 gallons per flush (gpf). Standard left-hand Polished Chrome trip lever included. Supply line not included. Combines with the K-20485 bowl to create a complete K-20450 Irvine™ toilet.