This is a SINGLE filter That replace these Brand names: Pleatco: PA100N | Unicel: C-7487 | Filbur: FC-1270 • Diameter: 7" • Length: 25 1/2" • Top: Open Hole: 3" • Bottom: Open Hole: 3" • Filter Area: 100 sq ft • Filter Material: REEMAY (4 oz/yard) Alternate Filter Names: CX870-XRE | CX870RE | C-870RE | Super-Star-Clear C4000 | Super-Star-Clear C4020 | Super-Star-Clear C4025 | Super-Star-Clear C4000S | 17-175-1037 | APCC7179 | 19902 | FC-6445 | PA100N-4 | PA 100N | PA100-N | SD-00551 | 090164710044 Used in pools / spas made by: Hayward and other manufacturers