Did Shure ever make an OEM microphone for RCA?

Date Updated: January 14, 2019 FAQ #5498
Question:
Did Shure ever make an OEM (Original Equipment Manufacturer) microphone for RCA?
Answer:

Yes. Around 1940, Shure provided a Model 399 crystal microphone to RCA. It was likely an accessory for RCA two-way radio equipment.

The Model 399 was based on the Shure Model 708S – a crystal "Stratoliner" microphone supplied with the S36 desk stand. On the S36 front, an RCA logo metal button replaced the Shure logo button.