This aquarium filter sponge is made of selected material for durable and practical to use. It can be used in seawater tank, fresh water tank, aqua-plant tank. And its strong filter ability and high density design can stable water quality and reduce fish died. It is easy to clean, and you can use aquarium filter for a long time. It also can help you . Features -Color:Black -Material:Sponge -Size:13.00X12.30X4.10cm/5.11X4.83X1.61in - Made of safe material, this aquarium filter doesn’t interfere with your tank's other accessories. - This filter pad helps in promoting a cleaning fish tanks. You can enjoy viewing the landscape clearly. - High water penetration efficiency and no water accumulation, this sponge pad is convenient to use. - With good water absorption and high permeability, this sponge pad can filtering and decomposing. - This filter sponge pad is perfect for both freshwater and saltwater aquariums and offers reliable performance. Package list: 2 x filter pad