Guardian Filtration Products 4 Pack Lot Filter Cartridges FITS: C5397 UNICEL C-5397 Filbur FC-2972 Pleatco PLBS100 RAINBOW PLASTICS Outside Diameter: 5 5/16" Length 17 3/4" Top Opening: 2 1/8" Bottom Opening: 2 1/8" Media Weight - 3 oz. SQ FT Media - 100' Sqft Unicel - C-5397 (C5397) Filbur - FC-2972 (FC2972) Pleatco  PLB-S-100 (PLBS100)