Bestway FlowClear 58012E Type III Filter Cartridge. Keep your pool water clear and clean with a Filter Cartridge (Type III, Type A/C) by Bestway®. This replacement cartridge measures 4.2 in x 8.0 in (10.6 cm x 20.3 cm) and is designed for 530-1,500 gal. (2,006-5,678 L) per hour filter pumps. They are easy to clean and sift dirt and debris out of your pool with your pump. Bestway® recommends replacing them every 2 weeks for best results.