The Seapora Filter Floss Pads are dense mechanical filter pads designed to remove fine/coarse particulate matter from your aquarium system. This process prevents obstructions in the biological media, thereby diminishing the risk of fish stress and disease. They also help keep your aquarium water crystal clear! Seapora Filter Floss Pads can be cut and shaped to fit any filtration system, such as: Canister Filters, Hang-On Filters, Trickle Filters, Pond Filters, Wet/Dry Filters, and other mechanical filter applications. Great for both freshwater and marine applications.