Newborn Brothers Model 255 quart caulking guns is a heavy duty tool for applying subfloor adhesives and other products packaged in 29 Oz. cartridges. The 18:1 high thrust ratio means you can push out the sealant or glue with a minimal amount of effort. The Super Smooth Rod with the high trust ratio allows you to dispense the product in a more even manner making it easier to place the sealant or glue properly.