Intex 637R Krystal Clear Cartridge Filter Pump Above Ground Pool 1000 GPH. Easy to use – simply replace the old cartridge with a new one every two weeks, Double insulated pump. The number on the actual item seen in the image is 637R, is the component part number that corresponds to the individual part for the system and this does not pertain to the model # 56637EG. Air release valve for air trapped inside filter chamber. Sediment flush falve at bottom of filter chamber. The item “Intex 637R Krystal Clear Cartridge Filter Pump Above Ground Pool 1000 GPH” is in sale since Monday, September 21, 2015. This item is in the category “Home & Garden\Yard, Garden & Outdoor Living\Pools & Spas\Pool Parts & Maintenance\Pool Filters”. The seller is “re-retailer” and is located in Anderson, Indiana. This item can be shipped to United States.