McVitie Weston valve collection, STC valve, type 3A/146J
STC valve, type 3A/146J, marked CV53 KB/F, (RMW/Y378 - McVitie Weston number), by Standard Telephones and Cables Limited.
STC valve, type 3A/146J, marked CV53 KB/F, (RMW/Y378 - McVitie Weston number), by Standard Telephones and Cables Limited.