One of the gun casemates of the Ouvrage de Pré-Giroud. The work is often called Vallorbe after the nearby town. The work was built between 1937 and 1939, so it is part of the first generation of post WW I defenses in Switzerland. The reason for this is that the work had to defend an important railway tunnel to France

Pré-Giroud was armed with three 7,5 cm guns, one 4,7 cm AT gun and four heavy machine-guns. With the German attacks on the French and Belgian forts in mind the fort was reinforced with three independant infantry casemates, each armed with two MGs. Pré-Grioud was one of the first Swiss forts to be opened to the public.