【Good Filtration】Our foam filter cartridge features a high-density mesh structure that filters a wide range of pool impurities. It effectively removes leaves, grass, hair, slag, pine needles, insects and other floating matter. Dimensions: 20 x 10 cm. Center hole: about 4 cm. 【Durable】This foam filter is made of high-quality sponge, flexible, resistant to deformation, environmentally friendly and reusable after cleaning for a long service life. 【Economical】Replacing filter cartridges is part of your daily pool maintenance. Regularly replacing paper filter cartridges would result in increased costs and waste. Washable and reusable foam filters are an ideal alternative to disposable paper filters. There is no need to replace filter sponges frequently. 【Widely Used】Our washable foam filters are compatible with Type A pool filters and most pool filters on the market. To keep your pools, aquariums, bathtubs, and spas clean, we recommend replacing them every two weeks for better filtration