Fluval C4 Power Filter featuring 5 stage of filtration; 2 mechanical, 1 chemical and 2 biological filtration for bar none performance. An integrated trickle chamber filled with C-Nodes is where biological fitration is super charged for fast and effeciant nitrification. Mechanical filtration is perfomed by a dual layer of foam and polyester and is easliy romoved for quick cleaning. The patented recirculation grid enhances mechanical filtration when the flow rate is reduced. A conveinent chemical insert basket directs water flow to maximize toxin removel. Maintaining only one stage at a time will preserve beneficial bacterial resulting in a stress free environment while ensuring aquarium water stays clear. Each filter is equipped with with Fluval C4 Poly/Foam, Activated Carbon, C-nodes and drip tray pad.The Fluval C4 Power Filter is ideal for use with aquariums upto 70 US gallon (265L).