A ballcock is attached to a rod and
a float ball. The ball lowers and opens the valve to let water in.
When the ball rises enough, the water shuts off. The handle is attached to a chain that lifts a flapper. A refill tube extends from
the ballcock to an overflow tube.

Uses an actuating unit in place of the flapper to allow water to flow. The actuating unit contains a disc that either snaps in place or contains a screw to keep in place.

Uses a tank ball in place of the flapper to allow water to flow.

The flush valve contains a float unit to allow water to flow. The bottom of the unit also contains
a replaceable seal.