【Wide application 】- Our biochemical balls can be used not only in marine biochemical filtration systems, but also in freshwater biochemical filtration systems, perfect for use in aquarium, pond and fish tank. 【Function 】- A great help in restoring the natural water quality and providing the most suitable living environment for your fish. 【How to work 】- When the water circulates in the internal space, the time is extended, using the nitrifying bacteria to achieve the effect of biochemical filtration 【Large volume 】Strengthen bacteria filtering effect, lightweight and easy to carry. Description: The biochemical ball is lightweight and easy to carry. It can be used not only in seawater biochemical filtration systems, but also in freshwater biochemical filtration systems. Perfect for using in aquariums, ponds and aquariums. Specification: Item Type: Filter Material aquarium tank Material: PVC+Sponge Black color Optional type: 16mm, 26mm, 36mm, 46mm, 56mm, 76mm Quantity: 50Pcs Package Included: 50*Biochemical Flask