max totoThe TOTO UltraMax utilizes TOTO's G-Max flushing system. The G-Max flushing system features a 3 in. wide flush valve, extra-large siphon jet, and a large trapway. This reliable combinationToto Ultramax uses the G max flushing system, while the Toto Ultramax II uses the Toto tornado flushing. Toto’s G max flushing system uses 1.6 gallons of water per flush, while the Tornado flush uses 1.28 gallons per flush.