General description The Pack Spa Filter Sponge is a washable replacement for Type S1 filter paper cartridges, designed to enhance your pool maintenance routine. These reusable foam filters are an economical choice, helping to reduce costs while ensuring effective filtration. Technical specifications Dimensions: 4.25 x 4.25 x 2.87 inch / 10.8 x 10.8 x 7.2 cm Center hole bore: 1.57 inch / 4 cm Material: Sponge Usage Replacing paper filter cartridges with these foam filters is a key part of routine pool maintenance, ensuring your pool remains clean and well-maintained. Other information Package Content: 4 * Filter Sponge