This spray gun is used to apply the Optimum tire gel. Because the tire gel is thicker than most dressings, it will not spray well from a spray bottle. So to use the optimum tire gel, we have incorporated spray gun use. As seen in our buffing with confidence video, we apply the tire dressing with the gun. The advantages are many. First, you will use far less material and be more cost effective. Second, the spray gun will quickly and evenly apply the dressing around the tire with no mess or runs. Third, the gun allows you pinpoint control so that no excess dressing gets sprayed on the wheel, the car itself, or the ground. And last, you can dress other trim quickly, and even wheel wells, evenly and more effectively. The gun only needs about 30PSI of air pressure, so even the smallest air compressor will do the job