The KOHLER Highline toilet tank features innovative Revolution 360 technology, an advanced flushing system that uses a powerful swirling motion to thoroughly rinse the bowl. This water-efficient toilet tank also utilizes 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. Kohler®, 44470-0, Toilet Tank, Highline Collection, 1.28 gpf Gallons per Flush, Left-hand Trip Lever Flush Handle, 14 in Rough-In, Floor Mounting, White