This sand filter is designed to filter and purify the water of your pool using sand as a filter medium. This is a very economical and low-maintenance option to keep your pool water looking pristine. Made of high-quality and high-density polyethylene, the sand filter is durable. With a diameter of 18 inch, it has a flow rate of 2377 gal per hour. The maximum working pressure is 50 PSI. To start the operation, 110 lb of filter sand (not included) are required. The filter is equipped with a multiport valve with 6 positions: filter (for filtering the body of water), backwash (for cleaning the filter medium), rinse (for flushing the filter system), waste (for bypassing the filter bed to waste), recirculate (for bypassing the filter bed to the swimming pool/spa) and closed (for shutting off all water flow to the filter). This sand filter is suitable for pool pumps of 1 HP.