Increase the efficiency of your tank's undergravel filtration system and introduce beneficial oxygen into the aquarium with Power Sweep Powerheads. Zoo Med Power Sweep Powerheads are designed to fit all undergravel stems from 3/4" to 1 1/8". They are self-rotating, which creates greater surface agitation to allow a high oxygen exchange rate. In addition, the rotating motion breaks down the surface film of dead bacteria which can inhibit oxygen exchange. All models feature a Venturi aerating system, adjustable flow rates and all mounting accessories. Can be used in fresh or saltwater. Great for use as a wave maker in marine tanks. CSA Approved.