"Round Bowl" - A measurement in inches from the center of the two seat bolts on the back edge to the furthest tip of toilet bowl that equals 19.4 or less.

"Elongated Bowl" - A measurement in inches from the center of the two seat bolts on the back edge to the furthest tip of toilet bowl that equals 20.6 or more.

"One-Piece Bowl" - Lotus does not currently fit on a one-piece bowl.