2 Guardian Pool Spa Filter Replaces Unicel C-4326Ra Pleatco Prb25-In-M Fc-2375, Antimicrobial -Bottom Opening: 2 - 1/8" -Top Opening: 2 - 1/8" -Outside Diameter: 4 - 15/16" (Also replaces 5") -Length: 13 - 5/16" 25 sqft Anti-microbial Media material Meets or exceeds OEM quality!! Filbur - FC-2375m----FC2375m UNICEL C4326RA---C-4326RA PLEATCO PRB25-IN-M ALSO FITS: UNICEL C-4326 ALSO FITS: Filbur - FC-2375 ALSO FITS: PLEATCO PRB25-IN