General description Our 4pcs S-Union Type A Filter Sponges are designed for effective filtration in pools, aquariums, and spas. Made from high-quality, reusable foam, these cartridges feature a high-density mesh structure that efficiently removes a variety of impurities, including leaves, grass, hair, debris, and insects, ensuring a clean and clear water environment. Technical specifications Size: 20 x 10 cm Center hole diameter: approximately 4 cm Usage For optimal performance, it is recommended to replace the filter sponges every two weeks. This practice helps maintain better filtration and keeps your pool, aquarium, bathtub, or spa clean.