Hayward S200 Series High-Rate Sand Filter 23-Inch High-performance filter. Applications-In-ground pools of all types and sizes, In-ground spas (residential or commercial), Water features (fish ponds, fountains, water gardens) Corrosion-proof, heavy-duty filter tank injection-molded of tough, durable ABS for dependable all-weather performance Large pressure sand/water drain for rapid winterizing or servicing; top diffuser assures even distribution of water over the top of the sand media bed All internal piping is 2-Inch to give smooth, free-flowing performance 6-position Hayward Vari-Flo control valve