Features: Just remove the old foam and replace with a new one. Our sponge is compressed packaging, please open the package and leave it for 24 hours to restore the original. Specifications: Material: foam sponge Color: black Size: about 5.9 x 2.6 x0.8 inches Package includes: 12 x Prefilter Sponge Notes: Manual measurement, please allow slight errors on size. The color may exist a slight difference due to different screen displays. The hole doesn't go all the way through the sponge.