2 Pack Guardian Pool Spa Filter - Antimicrobial - Replaces Unicel C-4950RA Pleatco PRB50-IN-M FC-2390M -Bottom Opening: 2 - 1/8" -Top Opening: 2 - 1/8" -Outside Diameter: 4 - 15/16" (Also replaces 5") -Length: 13 - 5/16" 50 sqft