Grace's Guide is the leading source of historical information on industry and manufacturing in Britain. This web publication contains 147,968 pages of information and 233,612 images on early companies, their products and the people who designed and built them.
of South Ruislip. The first UK company to manufacture a miniature valve.
1930s Established as the Freedman Valve Co
By 1949 manufacturer of miniature and midget thermionic valves for deaf aids, etc
1961 Manufacturers of thermionic and electronic devices, including subminiature valves, cold cathode tubes, filamentary and neon indicator lamps. 700 employees.