Looked up on 'Aunty Google', and Smiths Aircraft Instruments (based in London) supplied the British aviation industry wih 'all aircraft instruments'. So something British.
From
Smiths Aircraft Instruments :
Smiths Aircraft Instruments
1938. Ref AA below
of Cricklewood Works, London, NW2
1937 Part of the Aircraft and Marine Instruments Group of S. Smith and Sons (Motor Accessories) Ltd[1].
1937 Manufacturers and suppliers of aircraft instruments and accessories. "Essex" Fire Extinguishers. "Frazer-Nash" Wing-Tip Flare Device. "Harley" Aircraft Landing Lamps. Sole Concessionaires of "Husun" Navigational Instruments.
1939 See Aircraft Industry Suppliers
1944 Private company.
1944 One of 4 divisions of S. Smith and Sons (England) Ltd[2]:
1961 Manufacturers of all types of meters and instruments for aircraft.
Wartime suppliers write-up
1939 Suppliers to the Aircraft Industry
Smiths Aircraft Instruments, Cricklewood Works, London, N.W.2, the well-known specialists in the design and manufacture of all aircraft instruments from switches to the famous " Smith " Automatic Pilot.
The Smith Undercarriage Position Indicator has aroused a great deal of interest and is being standardised on many machines. It is completely self-contained with a screening device for night flying.
The Smith Remote Reading Equipment has recently been put on the market to meet the need for recording on the instrument panel the movement of such devices as flaps, retractable undercarriages, petrol-floa mechanisms.