The W-20HC Spray-All is a low volume, "high concentrate" spray applicator that produces strong dilution ratios for the toughest cleaning jobs. Weaker dilution ratios are achieved with metering tips. This venturi injection system uses standard city water pressure (35 - 125 PSI) to draw and blend a high concentration of chemical into the water stream to create a very strong chemical solution. The accurately diluted solution is then projected through the discharge hose and fan nozzle as a light, uniform spray on to a variety of surfaces. With a flow rate under 1 gallon per minute, this unit is great for spraying virtually any sized area or object slowly and completely with very little run-off.