General description 100% Brand New and High Quality, these Reusable Foam Filters are suitable for Bubble and Jetted Pure Spas, specifically designed as replacements for S1 Cardboard Filter Cartridges. Regularly replacing the filter elements is essential for daily pool maintenance. Cleaning and reusing these foam filters can significantly reduce your costs over time. Technical specifications Size: 10.8 x 7.3 cm Center hole diameter: approximately 4 cm Color: Blue Material: Sponge Package Contents: 30 x Filter Sponges Other information Note: Light shooting and different displays may cause the color of the item to differ slightly from the actual product. The measurement allowed error is +/- 1-3 cm.