Lifegard Aquatics Quiet One Aquarium Pump 5000 Patented Uni-Direction impeller eliminates need for noisy mechanical device. This allows the pump to High quality, corrosion resistant ceramic bearings help ensure quiet operation and longer life Small footprint, with energy-efficient motor, and high-flow rates Innovative "cooling chambers" provide air-cooling during dry use and water-cooling in wet applicatio Flow control dials on 800 1200 models