Baleen Filters 50 sq. ft. Pool Filter Replaces Unicel C-7457, Pleatco PWC50, Filbur FC-5150-Pool and Spa Filter Cartridges Model: AK-6037 Media Area 50 sq ft, 7 1/4" OD, Open Hole: 3 1/16" Top, Open Hole: 3 1/16" Bottom, 19 5/8" Long, AK-6037 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. 7000 Series Cartridge for Trimline C-50, Trimline C-100 Filter, replacement of Unicel C-7457, Pleatco PWC50 Baleen Filters Top: Open Hole: 3 1/16" Bottom: Open Hole: 3 1/16" 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.