[Premium] It is made of high quality sponge, powerful and durable, good flexibility and high elastic long-term use, can be easily bent without deformation or damage. Filter removal is part of daily pool maintenance and replacing the filter often can result in high cost. These clean and reusable foam filters will reduce your cost. [Easy processing] It is recommended to replace the ink cartridge once a week, which can be simply cleaned. You should see about 2 months of foam filters with 4PCS foam for easy replacement. [Reusable] The initial cost of the ink cartridge is slightly more than the carton, but exceeds significantly the life of the ink cartridge. These foam filters are longer than ink cartridges, which can be cleaned and reused for many times. [Wide Applications] Suitable for spraying Pure water countries, swimming pools, tubs, filters, water purifiers, air purifiers, sinks and fish tanks. [Size] The length of the swimming pool filter foam sponge is 20cm / 7.87in, inner