This Replacement filter cartridge replaces Unicel # C-4350, Pleatco # PDV50 and Filbur # FC-3072 while meets the OEM # C4350 specifications. This 23 ¾ inch long and 4 5/8 inch wide filter cartridge has 2 1/16 inch open holes both at its top as well as bottom. This high quality filter cartridge can handle the top load of 50 Square Foot and is best fit for Grecian Spa, Discovery Spas. Very easy to install this filter cartridge gives you clean and clear water for your spas and pools.