Pool Filter Replaces Unicel 5CH-45, Pleatco PFF50P, Filbur FC-2401 Filter Cartridge for Swimming Pool and Spa Media Area 45 sq ft, 5 5/16" OD, Open Hole: 2 1/8" Top, Open Hole: 1 1/2" Bottom, 10" Long, AK-90108 1 Year Warranty - Baleen Filters are made from Durable and Efficient USA Made Reemay Fabric - Washable Fabric Extends Your Filter's Life 45 sq. ft. Top Load Filter for Freeflow Spas Legend, replacement of Unicel 5CH-45, Pleatco PFF50P Baleen Filters Top: Open Hole: 2 1/8" Bottom: Open Hole: 1 1/2" Guaranteed Perfect Fit - Extremely Durable - Wash & Reuse - Most Energy Efficient - Withstands High Pressures & Temperatures Pre-Filters allow for quicker water balancing with fewer chemicals. Washing a filter will extend its life &amp; clean filters use less energy. The Jet Brush makes this quick and easy. Scum Magnets prevent scum andoil from making it to the filter for fewercleanings.