Mullard valve, type EF50, separate red painted metal canister, (RMW/Y281 - McVitie Weston number), by Mullard Limited.-1946

The EF50 radio valve, made by Mullard, was introduced commercially in 1946 but predates this - 1946 marked the year it was "demobbed" previously having being used by the British miliary Air Ministry VR91 or stores reference 10E/92. The EF50 was used in early British miliary radio sets during the Second World War and offered "a combination of technical innovation, versatility ... [and] distinctive appearance and the sheer volume of production." Many of the wartime radar sets containing EF50 became surplus in peacetime and were ingeniously converted into television receivers in the immediate post war years.