McVitie Weston valve collection, Mazda valve, type PEN3520
- Made:
- circa 1935
Mazda valve, type PEN3520, marked DUMMY, 7-pin base with one pin clipped, pinch marked PEN 3520/-, (RMW/Y302 - McVitie Weston number), by Standard Telephones and Cables Limited, c. 1935.