Marquis Spa 40 Square Foot Filter. Filter Measures 19 5/8 Inches Tall, 5 3/16 Inches Across, Top: 1 1/16 Inch Open, Bottom: 1 5/8 Inch Open. Unicel C-5637, Pleatco PPM40, Filbur FC-3637.
Outside Diameter:Â 5.1875"
Cartridge Length:Â 19.6250"
Top:Â 1 1/16 INCH OPEN
Bottom:Â 1 5/8 INCH OPEN