Mullard valve, type N.T.13, marked - Admiralty patt. 7426, pinch marked NT13, top pip broken, (RMW/J53 - McVitie Weston number), by Mullard Limited, 1933.
Mullard valve, type N.T.13, marked - Admiralty patt. 7426, pinch marked NT13, top pip broken, (RMW/J53 - McVitie Weston number), by Mullard Limited, 1933.