Air pressure is added to the water flow creating agitation that flushes out even the most stubborn clogs. The tip fits 1/2�, 5/8� and 3/4� hose fittings. Water pressure can be easily controlled with one hand by squeezing the handle of the heavy-duty spray gun. The insulated handle protects your hand when using hot water to flush the cooling system. The spray gun attaches to a standard garden hose.