The Blue Mule Rough Brush Foam-All is a foam cleaning system that continually creates foam through the stiff bristle brush. This venturi injection system draws chemical concentrate from any sized container, mixes it with water and projects the accurately diluted solution through the 50' hose and 44" handle as a wet, clinging foam. Mount the Rough Brush Foam-All anywhere 50-125 PSI water is available. Foam continually flushes debris from the bristles. Great for tough jobs that require scrubbing with an rough touch. The stiff bristled brush should not be used on paintwork or other delicate surfaces.