Premium Material: Approx. 108 x 73 mm (L x W) for Intex S1 type. The pool filter cotton is made of premium polyester fiber, strong and durable. Our pool filter sponge is suitable for Intex S1 type and most pool filters on the market, keep the pool, aquarium and spa clean. Save costs: Regularly replacing the paper filter cartridge is part of daily pool maintenance, which leads to increased costs and waste. Our reusable and washable filter sponges are an ideal replacement for disposable filter paper. You don't need to replace the filter sponges frequently. Keep water clean and fresh: The sponge cover fits directly over the water inlet of your filter. Captures particles and deposits and improves biological filtration. Good elasticity, strong tensile force, fast dust filtration speed, high dust filtration rate, with this filter, you can enjoy a safe and healthy massage spa. Type S1 Filter Cartridges: Type S1 filter sponge for Intex Pure Spas filter, air bubbles and water jet. Compatible