Western Electric 700 cavity magnetron. This US manufactured device was based on the design of cavity magnetron number 12, taken to the US in 1940 by the British Technical and Scientific Mission lead by Sir Henry Tizard. The mission, which became known as the Tizard Mission, sought US and Canadian help with developing and manufacturing British technology at a time when British resources were taken up with the war effort. The British cavity magnetron was a radical improvement on the technology of the time. It allowed radar devices to detect objects smaller than a metre and reduced the size of the radar apparatus. Photographed at the Office of Naval Research 75th anniversary commemoration of the Tizard Mission, at the Canadian Embassy, Washington DC, USA, on 17th November 2015.