General description These 4pcs Spa Filter Sponges are designed as washable replacements for S1 type paper filter cartridges. They are an essential cleaning tool for maintaining your pool, providing a cost-effective and eco-friendly alternative to traditional paper filters. Technical specifications Dimensions: 4.25 x 4.25 x 2.87 inches / 10.8 x 10.8 x 7.2 cm Material: Sponge Center hole drilling: 1.57 inches / 4 cm (approx.) Usage Replacing paper filter cartridges with these reusable foam filters is part of routine pool maintenance, helping to keep your pool clean and reduce costs. Other information Package Contents: 4 * Filter Sponge Color: Blue (As Pictures Show)