Hayward S166T92STL ProSeries 16-Inch 1 HP Sand Filter System, Twist Lock Cord Systems are designed for quick assembly and precise alignment of components Pumps and filters are performance-matched to provide maximum flow and energy efficiency Optional microprocessor pump timer available Filter bases are molded of rugged thermoplastic for long-lasting, all-weather performance 7-position Vari-Flo valve provides maximum flow at low pressure drop