Ferranti valve, type HD4, black on red printed label, pinch marked 343, top cap loose, (RMW/Y105 - McVitie Weston number), by Ferranti Limited, 1935.
Ferranti valve, type HD4, black on red printed label, pinch marked 343, top cap loose, (RMW/Y105 - McVitie Weston number), by Ferranti Limited, 1935.