Osram valve, type D.A./60, glass envelope missing, pinch tube broken, electrodes damaged, (RMW/C63 - McVitie Weston number), by Osram, 1930.
Osram valve, type D.A./60, glass envelope missing, pinch tube broken, electrodes damaged, (RMW/C63 - McVitie Weston number), by Osram, 1930.