High-quality material: Approximately 108 x 73 mm (L x W) for Intex type S1. The pool filter cotton is made of high-quality polyester fiber, which is strong and durable. Our pool filter sponge is suitable for Intex type S1 and most pool filters on the market, keeping your pool, aquarium, and spa clean. Save costs: Regularly replacing the paper filter cartridge is part of daily pool maintenance, which increases costs and waste. Our reusable and washable filter sponges are an ideal replacement for disposable filter paper. There is no need to frequently replace filter sponges. Keep the water clean and fresh: The sponge is placed directly over the filter's water inlet. It captures particles and deposits and improves biological filtration. Good elasticity, high tensile strength, and high dust filtration rate, this filter will ensure you enjoy a safe and healthy hot tub. Type S1 Filter Cartridges: Type S1 filter sponge for Intex Pure Spas filters, air bubbles and water jets. Compatible with