www.phcppros.com/articles/1350-ultra-high-efficiency-toilets

Ultra-High-Efficiency Toilets
September 1, 2016
The H2Option dual flush toilets and H2Optimum single flush versions offer a choice of a dual flush 0.92/1.28 gpf H2Option tank or single flush 1.1 gpf H2Optimum style. Their operations are driven by the Standard PowerWash siphon-jet bowl cleaning technology. The products have earned WaterSense certification. American Standard.