Reuse: The initial cost of this cartridge is slightly higher than a paper cartridge, but its lifespan is much longer than a paper cartridge and can be washed and reused multiple times. Regular Replacement: It is advisable to change a paper cartridge every week, while these foams can simply be washed and put back. Easy Maintenance: Replacing the paper filter element is part of daily tank maintenance. Replacing a conventional filter element can be very expensive. These washable and reusable foam filters will reduce your costs. Simple Operation: All you need to do is remove the filter when touching the electrode rod, as excessive chlorination will cause the foam to break quickly. Normal chlorine and bromine disinfection levels are fine, and these foams have been tested at normal levels. Notice: 1. The real color of the item may be slightly different from the pictures shown on website caused by many factors such as brightness of your monitor and light brightness.2. Please allow slight deviation for the measurement data.3. There may be an error of 1-3 cm.Package includes:5 x Swimming Pool Filter Foam Sponge