General Electric EM25A series microphones
The Shure Brothers Model EM25A communication microphone was produced for the General Electric company for their mobile radio units. There are a variety of models, mostly differentiated by their body color. EM25A, EM25E, EM25M.
The EM25 is basically a Shure 404C microphone in a custom body built for General Electric, and is easy to identify by it’s silver metal face grille.