Used, trace of use, has been tested and it works, some paint off, a sticker almost. Completely off, glue residue of the sticker, must be cleaned, view the pictures. German hand siren HSM7 in army color used by the German anti aircraft troops. And the air protection service, manufactured in the 1930s / 40s and still fully functional. As soon as the siren is operated by means of the crank, the air that is drawn in goes through.
A rotating paddle wheel at the front. Then the air is forced out through the openings on the. This creates a low hum / boom tone. When the crank is turned faster,...
