2-Pack Guardian Spa Filters Replaces C-4405, C-4405RA, Rainbow DSF 50, PRB25SF, FC-2387M,FC-2387,17-2464 Replaces Unicel C-4405, Filbur FC-2387, Pleatco PRB25SF PR (PRB25SF-JH-PAIR), Rainbow DSF 50 (DSF-50) Length: 6-5/8", Diameter: 5", Top opening: 2-1/8", Bottom opening: 2-1/8" 50 sq. ft. filtration area Antimicrobial filtration fabric (equivalent to Reemay with Microban Antimicrobial Product Protection) New in factory packaging