DESC: All Penguin BIO-Wheel Power Filters deliver simple, easy, 3-stage aquarium filtration...without the hassle of air pumps, valves, tubing or air stones. Now there are new features, new sizes, increased flow rates and a BIO-Wheel that's up to 50% larger! The new two-piece filter hood provides quick flip-top filter cartridge access. A noise- reducing vented cover ensures quieter operation. The adjustable mid-level intake increases water circulation throughout the aquarium and the larger 200 and 350 models feature extra media slots -- you can add an extra Rite-Size Filter Cartridge or Penguin Refillable Media Cartridge for enhanced chemical filtration.