Cunningham valve, type C-299, heavily gettered, glass envelope loose, (RMW/D152A - McVitie Weston number), by E.T. Cunningham, Inc., 1924.
Cunningham valve, type C-299, heavily gettered, glass envelope loose, (RMW/D152A - McVitie Weston number), by E.T. Cunningham, Inc., 1924.