This Cimarron 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-31588 or K-31589 bowl for a complete Cimarron elongated toilet.