McVitie Weston valve collection, Tungsram valve, type PV4018
Tungsram valve, type PV4018, (RMW/A171 - McVitie Weston number), by Tungsram Electric Lamp Works (Gt. Britain) Ltd..
Tungsram valve, type PV4018, (RMW/A171 - McVitie Weston number), by Tungsram Electric Lamp Works (Gt. Britain) Ltd..