These instruments were made for the U.S. Army or Navy by different companies,
Navy
Geiger Counter Radiac IM-74A/PDR-27C made by Admiral Co.
Radiac IM-207/PDR-27DX made by Hoffman Laboratories
IM141/PDR-27J Radiacmeter made by Chatham Electronics
AN/PDR-63 Radiac Set made by NUCOR (Nuclear Corporation of America)
Army
U.S. Army Radiac Set AN/PDR-T2 made by El-Tronics
CD
Civil Defense Instruments