Good FiltrationOur foam filter cartridge has a high density mesh structure that filters a wide range of impurities from the pool, it effectively removes leaves, grass, hair, slag, pine, insects and others floating materials. Dimensions: 10.6 x 7.5 cm. Center hole: about 4cm. DurableThis foam filter is made of high quality sponge, which is flexible, not easily deformed, environmentally friendly and can be reused after cleaning for a long service life. Cost SavingReplacing filter cartridges is part of your daily pool maintenance, regular replacement of paper filter cartridges will lead to 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 UsedOur washable foam filters are suitable for S1 type and most pool filters on the market. To keep swimming pools, aquariums, bathtubs and spas clean, we recommend that you replace them every fortnight for better filtration and to keep your pool clean. Advantage: Washable and reusable foam filter Easy to clean and store, durable Good breathability, corrosion resistance, water resistance No harm to human body, no pollution environmental, no peculiar smell, healthy Easy to maintain change Changing your filter cartridge is part of your routine pool maintenance and replacement regular cartridge can be quite expensive. Our sponge filter is washable, easier to clean and maintain than traditional paper filters. Durable Can be washed and used repeatedly High elasticity High quality material, not easy to deform and loosen