1 PACK MADE IN THE USA POOL AND SPA FILTER NEW IN FACTORY PACKAGING MEASUREMENTS: Diameter: 5" Length: 23 5/8" Top: Open Hole: 2 1/8" Bottom: Open Hole: 2 1/8" Filter Area: 75 sq ft Filter Material: Reemay Polyester (3 oz/yard) Popular brand part numbers: Pleatco: PCAL75 Unicel: C-4970 Filbur: FC-2930 Replaces the following filters: ?817-7500, SD-00592, Waterway 75, 17-175-1839, APCC7237, 17519 , PCAL 75 Cal Spas, Leisure Bay Spas , Rec Warehouse, Sunbelt Spas Waterway Plastics and other manufacturers