The Fluval U4 Underwater Filter is ideal for use in fresh, marine or reptile environments. It comes complete with the Adjustable 3-Way Flow Control feature, 2 Foam Pads, 2 Poly/Carbon Cartridges, and BIOMAX Biological Rings
The U4 is suitable for aquariums from 130 to 240 L (34 to 65 U.S. gal.).