Aquarium Bio Sponge Foam Filter Pads Replacement Compatible with FX4, FX5, FX6 Canister Filters Suitable for both freshwater and marine aquariums Pre-filter sponges capture micro-particles as water passes through, providing efficient water flow with less clogging for long-lasting filtration; helps maintain a healthy environment for aquatic life Package includes 12 foam filter pads; filter sponges should be replaced every 6-12 months as micro-holes gradually clog with debris, reducing filtration efficiency over time Easy to install and fits directly; this is a non-original aftermarket part designed to match and function properly Color: White Material: Sponge Package Contents: 12 x Fx4 Foam Filter Pads Only the above package content is included; other products are not included Note: Light reflection and different displays may cause the color of the item in the picture to appear slightly different from the actual item; measurement may vary by +/- 1-3 cm