11.   The ports are fitted with neoprene valve seats that hug the ball and keep water from leaking.

12.   The valve seat is made from soft brass, and corrosion or wear can damage the surface.

13.   The washer compresses against a valve seat in the faucet body and restricts the flow of water.

14.   Turning the handle causes the stem to rise and lifts the washer off the valve seat, enabling the water to flow.