McVitie Weston valve collection, National Union valve, type 12A7
National Union valve, type 12A7, pinch marked 24, (RMW/H27 - McVitie Weston number), by National Union Radio Corporation.
National Union valve, type 12A7, pinch marked 24, (RMW/H27 - McVitie Weston number), by National Union Radio Corporation.