Water-cooled 'Protexray' tube (6 K.W. Model) no. 32649
Water-cooled 'Protexray' tube (6 K.W. Model) no. 32649, by Cuthbert Andrews Limited, London, England, 1932.
Water-cooled 'Protexray' tube (6 K.W. Model) no. 32649, by Cuthbert Andrews Limited, London, England, 1932.