Product name: Swimming pool filter sponge. Product color: blue. Product size: 100*200mm. Quantity delivered: 4 pieces Sponge filters can filter many pollutants in swimming pools, prolong the service life of filter media, ensure efficient water flow, reduce clogging, and achieve long-term filtration and cleaning. Great for S1 filters. Durable: The foam filter has good flexibility and high elasticity. The life of the foam filter is longer than that of the filter element and can be cleaned and used many times. Cost savings: Replacing the filter element of a paper filter is part of routine pool maintenance. Save money with these clean, reusable sponge foam filters. Applicable: Our washable foam filters and most swimming pool filters on the market are suitable for swimming pools, bathrooms and aquariums. The vacuum packs we use deform when opened, but return to their original state in water.