【Good Filtration】 Our foam filter cartridge features a high-density mesh structure that filters a wide range of pool contaminants and effectively removes leaves, grass, hair, debris, pinewood, insects, and other floating substances. Size: 10.6 x 7.5 cm. Center hole: approx. 4 cm. 【Durable】 This foam filter is made of high-quality sponge, is flexible, does not deform easily, is environmentally friendly, and can be reused after cleaning for a long service life. 【Cost Savings】 Replacing filter cartridges is part of daily pool maintenance; regularly replacing paper filter cartridges leads to increased costs and waste. Washable and reusable foam filters are an ideal alternative to disposable paper filters. Filter sponges do not need to be replaced frequently. 【Widely Used】Our washable foam filters are suitable for Type S1 and most pool filters on the market. To keep your pool, aquarium, bathtub, and spa clean, we recommend replacing them every two weeks to ensure better filtration and keep