Suitable for: Compatible with for 1580/1840GPH Pressurized Biological Pond Filter and for VIVOGROW 1580/1840GPH Bio Pressure Pond Filter. Upgraded formula: We use dual density combination, yellow sponge with high density, blue sponge with normal density, different density combination,, which better filters fine particles and adsorbs odors without restricting the flow of water, providing a healthier environment for your fish. Efficient: Provides both mechanical and biological filtration, effectively trapping debris, food scraps, waste or other impurities in the water, preventing them from entering the aquarium and keeping the water clean. Longer life cycle: Made of soft foam, our sponge pads are highly elastic and have good breathability and water permeability, no need to worry about sucking the fish away or obstructing the normal water flow. Washable and reusable after cleaning. Sufficient quantity: Includes 4 sponge bio filter pads (2 pieces of yellow sponge, 2 pieces of blue sponge) Note: Due to the vacuum packaging the sponge pads may look thinner, which does not affect the filter effectiveness and you can soak them in water for 5-10 mins to get its dimension, if you need a quick rebound, you can use water to rinse the product. Color:Yellow & Blue Material:Sponge Package Contents: 2 * yellow sponge 2 * blue sponge Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.