A.C. Cossor Ltd., Cossor House, Highbury Groove, London N.5, England.
A.C.Cossor can trace its roots back to 1859, when it was founded long before radio was discovered. They made thermometers and barometers, specialised electrical glassware, to later include an early cathode ray tube, made in 1902 and "R" valves for use in the later years of WWI at their first factory at Highbury, London.

In 1922, Cossor launched a radically new type of valve which they designed in-house, establishing their name in the frontrunners of radio. They went from strength to strength selling valves and radios kits, diversifying to electronic instruments, including an oscilloscope.
The company initially entered the business of manufacturing radio sets by selling their products in kit form, adopting the slogan "Kings of the Air", later manufacturing for sale, in 1930, their first complete model. The Highbury factory was continuously developed until 1932 when they ran out of space, resulting in a decision to build their second factory, at Leyton, where they made radio cabinets from 1934.