Klaxon (Smiths)

The Klaxon is hand operated.
The sound is generated by a ‘teethed’ wheel, which activates a steel membrane through a screw in the middle of this membrane. Adjustment to get the desired sound can be done by turning  this screw. The brace is a replica.

There have been many brands of vehicle horns (‘Klaxons’); I managed to buy a Smiths.