Intex Replacement Pool Pump Filter Cartridge "A". Ffor #58603EG/28603EG (530 Gallons), #56637EG/28637EG (1,000 Gallons), #56635EG/28635EG (1,500 Gallons) Pumps. It ensures ultimate filtration with its easy-to-clean Dacron filter material. This filter cartridge is compatible with Krystal Clear Cartridge Filter Pump and comes shrink-wrapped with a litho label for easy identification. Replace the filter cartridge every 2 weeks for optimal performance.