and high quality,Reusable foam box.Suitable for Bubble and Jetted Pure-spas. for Replacement of S1 carton.Replacing the filter elements of paper filter is part of the daily maintenance of the pool. These cleaning and reusable foam filters will reduce your cost.The initial cost of the cartridge is slightly higher than that of the cartridge, but the cartridge life is longer for a long time.More durable than the carton, and it can be washed and reused many times.Size: 10.8x7.3 cmCenter hole drilling: Approx 4 cmNote: It takes 2 hours for the compressed product to recovercolour: blueMaterial: spongePackage Contents:16 x Filter SpongesOnly the above package content, other products are not included.Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.