From the Manufacturer
American Standard 735105-400.021 Champion Toilet Tank Cover, BoneMeet the Champion , the undisputed leader in high performance toilets. With the industry's widest 2 3/8" trapway and 4" flush valve, it created a plunger free world for homeowners and virtually eliminated clogged toilet call backs for plumbers. The Champion will move a mass 70% larger than the industry standard. It achieves the highest bulk removal rating of 1,000 grams and will even flush a bucket of golf balls! Which means you can flush with confidence and never worry about plunging a toilet again. American Standard 735105-400.021 Champion 4 Toilet Tank Cover, Bone Features:; American Standard Toilet Tank Cover; Champion 4 Collection
For Concealed Arms; Extra Left-Hand Hole; Rear Overflow.