This is a circa 1920 internally-illuminated, opal glass letter porcelain enamel sign. The entire sign cabinet of this early lightbulb sign is copper, which is a major factor in the sign’s excellent condition. Most signs of this era were constructed of tin (sheet metal), and were therefore subject to rusting. Once copper is oxidized it is incredibly durable and almost immune to the elements. Early electric signs with opal glass are rare.
G.E. (General Electric) was formed out of a merger between Thomas Edison’s Edison Electric Company and the Thomas-Houston Electric Company in 1893, all of which was arranged by J.P. Morgan. Today, both companies are still operation under GE.