KOHLER Kelston 1.28 GPF Single Flush Toilet Tank Only with AquaPiston Flushing Technology in BiscuitKelston 1. 28 GPF Toilet Tank with AquaPiston Upgrade your bathroom experience with the KOHLER Kelston 1. 28 GPF Toilet Tank in Biscuit, featuring the powerful AquaPiston Flushing Technology. This efficient and elegant component saves water without compromising performance, while coordinating seamlessly with the rest of the Kelston collection for a cohesive design. Key Features: Efficient Flush: Uses only 1. 28 gallons per flush to conserve water