General description Reusable and washable filter sponges designed for Type H swimming pool cartridges. These foam filters are a cost-effective alternative to traditional paper filters, offering long-lasting performance and ease of maintenance. Technical specifications Material: Sponge Color: Blue Size (HxW): 10.2 x 9 cm / 4.01 x 3.54 inches (Approx) Center Drilled Hole: 30 mm (Approx) Package Contents: 20 x Filter Sponge Measurement allowed error: +/- 1-3 cm Usage Foam filters can be washed and reused multiple times, significantly reducing maintenance costs. It is recommended to change paper filters weekly, while these foam filters can simply be cleaned and reattached.