Fluval C4 Power Filter, Fish Tank Filter for Aquariums up to 70 Gal. C4, Black Description Seller.comFluval C Series Power FilterMaximum Versatility and Premium PerformanceEngineered to create superior water quality, the Fluval C Power Filter provides extensive 5-stage filtration for outstanding results. The Power Filter is designed to provide maximum surface area and optimum dwell times in all stages of the filtration process.New 5 Stage Filtration SystemStage 1 & 2: Mechanical- Poly/Foam Pad Effective mechanical filtration is essential for efficient chemical and biological filtration. The large surface area of the Poly/Foam pad effectively performs two stages of Mechanical filtration.