Voted Top Antique Store by 5280 Magazine Readers in the Denver Metro Area
The General Electric 97U29 microphone was manufactured by Shure Brothers from around 1948 through 1968. It's a sturdy, all metal microphone and typically would contain a Shure 99A86 element.
From the 1956 Shure Brothers Catalog:
"510" Microphone Assembly
Controlled reluctance microphone and desk stand assembly-ideal for fixed-station used in all types of communications work. Has a built-in switch for controlling both the microphone circuit and an external relay or control circuit. Replacement for Mfrs. Model No. CR 84. Model 510MD list price: $42.50