The cases were made of Bakelite, which formed the base, sides, and top.  The front and back pieces were polished metal castings.  They are most often seen with cases of nickel silver and black Bakelite though they were also available with brass finished or white lacquered metal pieces with a brown Bakelite frame. 

The dial was a piece of translucent plastic lit from behind by a small bulb.  A lever on the back controlled the brightness of the light.