Letter are mounted as individual words on an aluminum angle bracket. They are attached with threaded aluminum bolts into in-line stud bosses. The angle bracket can be painted. The backs of the letters can be unfinished (standard) or finished for an additional cost. This option is only suitable for letters between 4" and 30" tall with a minimum thickness of 1/4".
See the Technical Drawing for more details

The mounting option does not come with a mounting template. The customer must drill their own mounting holes in the rail and supply their own hardware to attach the rail to the mounting surface.