3/4″ Valves have a small rubber “button” in them that makes a seal when the plunger is moved by the float. This button is the heart of the valve and is a “wear & tear” item. It is a good idea to keep some on hand so repairs can be made when the valve seems to be dripping or won’t shut completely off. The buttons can be flipped over and re-used once and this will work to save using a new button for a while. But sooner or later you’ll need some of these – go ahead and purchase some when you get your fountain.These buttons are used on the valves in larger fountains that use the 3/4″ valve – Watermatic 300, 1000, Omni 3, 5, 10, Cattlemasters and Watermasters, ThriftyKing CT 2, 4, 6.