Failure to keep your water level right can result in damage to pool equipment. The Pentair Automatic Water Filler protects your investment by using simple, reliable float mechanisms to monitor and control the water level in your pool or spa. When water drops below a preset level, the unit meters in additional water until the proper level is restored. If water levels are too high, the built-in overflow will take the right amount of water out of the system. The body of the Automatic Water Filler is tough, corrosion and chemical resistant A.B.S. polymer for years of trouble-free service. Only 7 inches in diameter, with models for both standard and vanishing edge pools, the Automatic Water Filler is easy to incorporate into new designs or renovations.