The FillStar water leveler control system maintains constant and consistent water level in a pool or spa. Constant changes in water level can cause damage to your pool equipment. The easy to install FillStar reduces the need for continuous water monitoring. The Fill Star features an ABS body and pre-glued PVC connections, transition glue is not required. It has a overflow port with a 1/2'' cap, and also the top lid matches our standard skimmer lid.