The trip lever Avalon overflow plate stops the water flow by lifting the handle and pressing the handle down to release the water in the bathtub. With the trip lever down, the plunger is lifted and the drain is open, when the trip lever is up, the plunger is forced down and the drain is closed. And if the tub is accidentally overfilled, excess water can still run down the overflow tube behind the trip-lever plate and can drain away because the plunger is hollow.