HWD 16in Pro Series TM Above Ground Sand Filter Superior filtration from the inside out. The Pro Series filter features an integral top diffuser that evenly distributes unfiltered water over the sand media bed in a cascading, umbrella-like pattern. This allows the greatest filtration possible from every square inch of sand. Then the self-cleaning underdrain assembly, with its 360 slotted laterals, provides a fast, balanced flow of clear water back to the pool while allowing for more thorough backwashing. Best of all, the Pro's full-flow technology reduces your energy costs because the filter operates for shorter periods. Seven-position valve puts you in control. The patented, multiport control valve developed by Hayward was designed with seven pool filter positions. An easy-to-use lever-action handle lets you quickly dial any function. Long-lasting convenience. You can easily access the Pro Series filter assembly for simple servicing via the unique folding ball joint in the laterals. A corrosion-proof housing protects the filter from severe weather for years to come. Pro Series Specifications Filter type: High-rate sand: No. 1/2 silican sand (.45 mm - .55 mm) Filter tank: Molded polymeric Underdrain: 360 self-cleaning slotted laterals, precision installed in ball-joint assembly Control valve: Four or seven-position, top-mount Vari-Flo™ valve with level-action handle Valve fastening: Flange clamp design Pump and motor: PowerFlo Matrix Series Pump - 115 volts Mounting base: Injection-molded ABS