Coatings can be thinner, like stains, or thicker, like exterior latex paint. Stains require smaller tip sizes and less pressure, but paints and heavier coatings need larger tip sizes and more pressure. A sprayer’s tip size can refer just to the size of the opening, as in a .015 tip. It might also indicate the fan size in inches, along with the tip opening, such as a 515 tip. In this example, the spray pattern will cover 5 inches and the tip opening is .015.