The initial cost of the cartridge is slightly higher than the cartridge, but the service life of the cartridge is long for a long time. Brand new and high quality, reusable foam box. Replacing the filter elements of the paper filter is part of the daily maintenance of the pool. These clean, reusable foam filters will keep your costs down. Fits Bubble and Jetted Pure spas. for S1 cardboard replacement. Durable than cardboard, it can be washed and reused for many times.Note: The data is all manual measurement, please allow 1-3cm error, due to of the light and display difference, there will be a certain color difference, depending on the physical object received Delivery Quantity: (according to the main image)