This tube is similar in appearance to the de Forest DV3, but electrically different. It was designed for the US Navy in 1924 as a short wave RF amplifying receiving type. The base is made of isolantite ( a kind of porcelain) Also known to have had a 1.1 amp filament. The tube was made specially for the SE-1805 aircraft amplifier. QST magazine for February 1932, page 75 shows an illustration of the tube and it is among others offered for sale as "Military surplus".
