1944 advertisement from Belmont Radio promotes blood donations during World War II. Belmont was a Chicago company with operations on Dickens Avenue. It kept a low profile prior to WWII because it made radios sold with other companies names, including Goodyear, Delco, Coronado for Gambles department store, Airline for Montgomery Ward and Truetone and Jewel for Western Auto.
The earliest references I've found to Belmont radios were in 1926. During World War II Belmont built aircraft radio for the military, such as the BC-348 receiver (aka AN/ARR-11).
Belmont was acquired by Raytheon in 1945 and Raytheon sold Belmont to Admiral in 1956. Reportedly the company closed its doors in 1957.
Size: 3" x 5"