One of the listening devices designed for the Dutch Army.

Dutch listening device

Plaek Phibunsongkhram(Center), The prime minister of Siam during WW2, check the army flag of III/5e REI troop (Régiment Etranger d'Infanterie - Foreign Infantry Regiment) with Croix de guerre, after defeated France Foreign Infantry Regiment at Phum Preav,Cambodia, during The Franco-Siam War

The end of the battle of Phum Preav 

Caption from Internet source: Slovak Home Army troops man a 20mm kulomet vz.36 light anti-aircraft gun. This piece was manufactured in Switzerland. It could fire at the maximum range of 3,300 feet (height) and could fire 830 rounds per minute. It was manufactured between 1930 and 1938.