FILTER: Intex filter cartridges feature a thicker, heavier Dacron paper for more efficient filtration and to keep your pool clean and clear all season long (2 Pack) PRODUCT INFO: 13.5 square feet of Dacron filament media with 63 pleats and is easy to clean and is (L x W) 5.75 x 10 inches FILTER CHANGE: Intex recommends replacing this filter cartridge as often as every 2 weeks for peak pump performance and to keep your water clean and crystal clear INTEX FILTER: Replaces Intex 29005E filter cartridge and fits any filter pump that uses Intex 59905 filter cartridges, and extend the life of this filter by periodically hosing it down until it shows signs of wear and deterioration COMPATIBLE WITH: Krystal Clear Model's: FP621R, 520R, 633, 520, 51, 59901e, 59905E; Intex: 56611, 56621, 58621 (pre-2004), 56633, 56631, 58621, CS8221/CS8231, CS8111, 634RC, 634T, 633T