Osram valve, type L.M.11, side contacts for grid and anode, otherwise uncapped, (RMW/C12 - McVitie Weston number), by Osram, c. 1923.
Osram valve, type L.M.11, side contacts for grid and anode, otherwise uncapped, (RMW/C12 - McVitie Weston number), by Osram, c. 1923.