Hivac valve, type AC/YY, pinch marked AC/YY, (RMW/G43 - McVitie Weston number), made by Hivac Limited, aka the High Vacuum Valve Company, London.
Hivac valve, type AC/YY, pinch marked AC/YY, (RMW/G43 - McVitie Weston number), made by Hivac Limited, aka the High Vacuum Valve Company, London.