SONABEL Type BOF Horn Compressor, 6V I guess for a complete horn you also need the pneumatic horns, that would be connected using a firm hose to the outlet of the compressor.
1906 FIAT BREVETTI COUPÉ DE VILLE Coachwork by Carrozzeria Italiana Cesare Sala, Milan
1906 FIAT BREVETTI COUPÉ DE VILLE Coachwork by Carrozzeria Italiana Cesare Sala, Milan Chassis No. 788 Coachwork No. 5699 Location: Siena, Tuscany, I..