CR81 and other OEM Models - Hercules or Rex

Date Updated: November 4, 2019 FAQ #1198
I have an old two-way radio mic that was made by Shure. What info can I find on it? It was made by Shure for another company.

This microphone was an OEM (Original Equipment Manufacturer) model, i.e., Shure made the microphone for another equipment manufacturer.

The CR81 was a Controlled Reluctance (Magnetic), high-impedance (14k ohm) model, light brown in color, made for Revere (Camera), a tape recorder manufacturer. The CR81 probably is from 1950s or 1960s when reel-to-reel tape recorders were popular.

The outer case design, named Rex or Hercules, was reused for many microphone models with many different case colors. Some had controlled reluctance elements, some dynamic elements, some crystal elements. Example models are:

Model 510 - standard Shure model
CA80A - OEM model for Ampro; front nameplate reads "AMPRO NO. 189"
CR10 - OEM model
CR10F – OEM model for Zenith
CR10K - OEM model
CR80D - OEM model
CR80F - OEM model for Columbia; for Bell & Howell; for TDC
CR80G - OEM model for Wilcox-Gay Recordio (home record cutter)
CR80J - OEM Model for Telectro (used by U.S. Army)
CR80Y - OEM model
CR81 - OEM model for Revere
CR81A - OEM model
CR81F - OEM model
CR84A - OEM model for Motorola
CR88B - OEM model for General Electric
CX70 - OEM model with crystal element
CX80 - OEM model with crystal element
CX80C - OEM model for Bell & Howell
DR80G - OEM model for Recordio/WG
MI-12014-A OEM model for RCA
TM125 -OEM model
21026 - OEM model with controlled reluctance element
97T29 - OEM model for Bendix Radio
97U29 - OEM model for General Electric