This 18:1 Pro Caulk Gun is a manual caulking gun that takes industry standard 29 oz. cartridges (large size). Its durable design is perfect for frequent high volume use and features a pivoting barrel for seamless caulking around corners, curves, and tight spaces. The 18:1 mechanical advantage provides 18 lbs. of application pressure for each lb. of force applied to the trigger handle, perfect for applying high viscosity caulks and adhesives. In addition, our caulking gun features an instant pressure release tab, to prevent excess caulk leakage and a convenient pin to puncture the inner seal of the adhesive cartridge.