McVitie Weston valve collection, STC valve, type 4017B
- Made:
- circa 1918
STC valve, type 4017B, defective cathode, (RMW/A200 - McVitie Weston number), by Standard Telephones and Cables Limited, c. 1918.
STC valve, type 4017B, defective cathode, (RMW/A200 - McVitie Weston number), by Standard Telephones and Cables Limited, c. 1918.