Pool Filter Replaces Unicel C-4405, Pleatco PRB25 SF PR, Filbur FC-2387 Filter Cartridge for Swimming Pool and Spa Media Area 50 sq ft, 4 15/16" OD, Open Hole: 2 1/8" Top, Open Hole: 2 1/8" Bottom, 6 5/8" Long, AK-3026 1 Year Warranty - Baleen Filters are made from Durable and Efficient USA Made Reemay Fabric - Washable Fabric Extends Your Filter's Life 50 sq. ft. Skim Filter for Dynamic Series IV Model DSF, replacement of Unicel C-4405, Pleatco PRB25SF-PAIR Baleen Filters Top: Open Hole: 2 1/8" Bottom: Open Hole: 2 1/8" Guaranteed Perfect Fit - Extremely Durable - Wash & Reuse - Most Energy Efficient - Withstands High Pressures & Temperatures