, reusable foam filter. Compatible with Intex Bubble and Jetted Pure-spas. Designed as a replacement for S1 cartridge. Replacing paper filter elements is part of regular pool maintenance. These washable and reusable foam filters help reduce ongoing costs. While the initial cost is slightly higher than disposable cartridges, these filters offer longer service life and greater durability. More durable than standard paper cartridges and can be cleaned and reused multiple times. Size: 10.8 x 7.3 cm Center hole: Approximately 4 cm Note: Allow 2 hours for compressed product to fully expand after unpacking. Color: Blue Material: Sponge (foam) Package Contents: 16 x Filter Sponges Note: The package includes only the items listed. Other accessories are not included. Note: Lighting conditions and monitor settings may cause slight color variations between the image and the actual product. Measurement tolerance is +/- 1-3 cm.