The Multi-Function Cleaning Gun gently loosens stubborn dirt. No separate brush is needed! The air flow from the gun vibrates the bristles for constant, effortless cleaning. The cleaners/water come from separate inner infusion tube, so it creates sufficient lubrication when the surface is being brushed. The Multi-Function cleaning gun is perfect for cleaning delicate or hard-to-reach surfaces, such as engines, wheels, tires, vents, trunk, door jams, etc.. Best results are achieved by pre-spraying the detergent and allow it to presoak for 30 seconds, then agitating the surface with the gun with water.