the desired length and optionally control and drive the mastic pump 10 with an electric motor so as to apply the same size of mastic bead 13 a to the trim product 1 regardless of how fast the trim material 1 is moving through the device the control unit can also optionally to control and drive the bottom drive roller 3 using a motor also shown in fig2 are wheels 16 and a handle 17 used to easily move the device around the job site or from site to site fig3 shows a right side view of an embodiment of the present invention with the cam assembly 18 and part of the guide wheels 19 removed so that the internal parts of this embodiment of the device may be seen generally in this view the product moves from right to left through the device as it is being dispensed as indicated by the arrow on the left side of the view the bottom drive roller 3 is normally mechanically linked to the advance lever 4 such that when the advance lever 4 is rotated counter clockwise it mechanically engages the bottom drive roller 3 to rotate in the same direction when the advance lever 4 rotates clockwise the bottom drive roller 3 is mechanically disengaged and.