API Filstar Micro Filtration Pads provide ultra-fine water filtration and polishing for a remarkably clear aquarium. These cotton filter pads remove extremely fine waste, particles and sediment from your aquarium water, preventing cloudiness and maintaining a healthy aquatic environment. Microfiltration pads for Filstar XP aquarium filtersPolishes your aquarium water to help make it crystal clearFits API Filstar XP1 Small, XP2 Medium, and XP3 Large canister filtersFilstar XP Micro Filtration Pads satisfy your fish tanks mechanical filtration needs. Maintenance: Replace the cotton pad every time the water is changed or at least once a month. Instructions: Place a cotton pad into the top filtration compartment.