dentifrice it would not be feasible to fill a tube through the small nozzle opening the filling time would be prohibitively long thus in blow molding the tubes would be blown without either the upper nozzle portion or without the permanent lower bottom portion depending on whether they are to be bottom or top filled when blow molded without the nozzle portion the tube would be filled from the top and a nozzle fitment attached when blow molded without the permanent bottom portion the tube will be filled from the bottom and crimp sealed the tubes can also be formed by extrusion when formed by extrusion the tube will be extruded in a continuous length and cut into sections of the desired length the shoulder nozzle portions will be separately formed by injection molding or an equivalent technique then in a separate step the shoulder is heat sealed to the tube the tube is open at the bottom and is thus bottom filled after filling the bottom is sealed by a crimp heat seal in the use of either blow molding or extrusion the tubes are provided with at least one view window and a nozzle the view window is a clear or substantially clear transparent stripe longitudinally along the tube wall this can be along any wall of the tube it need only be of a clarity width and length so that the amount of contents remaining in a tube can be determined in most instances the tube will be opaque with a narrow view window the tube will usually be opaque since it is easier to put printed instructions and decorations onto an opaque surface the view window will.