The Albion 80 oz. (2-1/2 Quarts) Air Assist Bulk Loading Gun generates 120 psi of force. When a contractor has a project that requires the big guns, this is the one! Barrel Diameter is 3-3/8" and is 16" long; comes with 7/8" Nozzle. Manual pull allows better loading sensitivity. (The air assist is only for application, not for loading caulk/chinking.) Use the 3-1/4" Reducer Cap to work with the Albion Follow Plate for quick reloading of caulk or chinking.