The Fluval C2 Bio-Screen Replacement Media provides massive biological surface area for friendly bacteria to colonize. It also works to block debris and evenly distribute the water flow before it drips into the Power Filter's biological trickle chamber. The Fluval C2 Bio Screen Replacement Media is exclusively designed for the Fluval C2 Power Filter and will work to keep your aquariums crystal clear. Allows area for friendly bacteria to colonize Works to block debris and create an easy water flow Country Of Origin: Italy