Flushing systems don't get any better than this one. The Champion 4 system features the industry's largest flush valve. The 4 in. Accelerator flush valve pushes water into the bowl three times faster than a standard 2 in.. The system also has the industry's largest siphon outlet at 2-3/8 in.. This extra wide fully glazed opening can move a mass almost 70 percent larger than a standard 2 in.. It achieves a maximum MaP score rating of 1,000 grams. you may never have to use your plunger again. It also helps keep itself cleaner with our exclusive EverClean surface. And it's all backed by a 10 year warranty on china and trim.