Aqua Kleen AK-60034 Unicel Replacement Filter Cartridge for Swimming Pool and Spa 30 sq. ft., 7" OD, Open Hole: 4 1/8" Top, Open Hole: 4 1/8 Bottom, 7 1/4" Long, AK-60034 Exact Fit for Unicel: C-7330 Exact Fit for Pleatco: PMA30-2002-R Exact Fit for Filbur: FC-1003 Guaranteed Perfect Fit - Extremely Durable - Wash & Reuse - Most Energy Efficient - Withstands High Pressures & Temperatures