1.SET INCLUDES: 1Type-A cartridge replacements,For above-ground pools. Floating sponges will save the life by collecting oil.2.EASY MAINTENANCE: Ensures your pool water is clear of debris and gunk that build up over time. Collects and removes chemicals and metals such as copper, excess chlorine, sunscreen, deodorant, and hair-care products.3.DURABLE MATERIAL: Crafted of a heavy-duty Dacron-blend materialpolypropylene and Dacron plastic fibers. The thick paper its constructed of has tight pleats for superior filtration. Filters 1,500 gallons of pool water per hour.4.CARE AND REPLACEMENT: For optimum results, replace the cartridges with a new one every two weeks. Or scrub the fabric with a cartridge cleaner tool and rinse with a powerful hose to extend the life of the cartridges.