In a Single-flush gravity toilet, the bowl, trapway and tank are engineered for precision. Gravitational force creates a strong siphon and the AquaPiston canister allows water to flow into the bowl from all sides (360 degrees). This increases the power and effectiveness of the flush.
Moreover, the 3.2 ratio of the flush valve drastically improves overall performance. Unlike a 3-inch flapper, leaks are less common due to the durable canister design with 90% less exposed seal material. The light-touch canister flush also requires a lower actuation force.