McVitie Weston valve collection, SFR valve, type E506
SFR valve, type E506, pinch marked 15369, evacuating pip and filament broken, (RMW/Y685 - McVitie Weston number), by Societe Francaise Radioelectrique.
SFR valve, type E506, pinch marked 15369, evacuating pip and filament broken, (RMW/Y685 - McVitie Weston number), by Societe Francaise Radioelectrique.