McVitie Weston valve collection, STC valve, type 4212D
STC valve, type 4212D, glass stem marked A351, (RMW/D111 - McVitie Weston number), by Standard Telephones and Cables Limited.
STC valve, type 4212D, glass stem marked A351, (RMW/D111 - McVitie Weston number), by Standard Telephones and Cables Limited.