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 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 water, preventing them from entering aquarium and keeping 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 fish away or obstructing 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 vacuum packaging sponge pads may look thinner, which does not affect 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 hot water to rinse product. Color:Yellow & Blue Material:Sponge Package Contents: 2 * yellow sponge 2 * blue sponge Only above package content, other products are not included. Note: Light reflection and different displays may cause color of item in picture a little different from real thing. The measurement allowed error is +/- 1-3cm.