General description These 18 reusable and washable foam filters are designed specifically for Pure Spa hot tubs, suitable for both bubble and jetted models. They serve as a replacement for the S1 cartridge filters, making them an essential part of your pool's daily maintenance. These high-quality foam filters not only reduce your overall costs but also offer a longer lifespan compared to traditional paper filters. Technical specifications Size: 10.8 x 7.3 cm Center hole diameter: 4 cm Material: Sponge Color: Blue Other information Package Contents: 18 x Filter Sponges Note: Light and different displays may cause the color of the item in the picture to differ slightly from the actual product. The measurement allowed error is +/- 1-3 cm.