The Mle 1939 (Model 1939) was a French anti-personnel bounding mine used at the start of the Second World War, it was developed largely in response to the German S-mine bounding mine.
The plans escaped to the US via Major Pierre Delalande, a member of the French Corps of Engineers, and were used as the basis for the American M2 bounding mine which saw wider service during the war but was considered largely ineffective.
A rectangular thin metal plate positioned halfway up the main body of the mine provides additional support.
When the fuse is triggered, a flash travels along the steel tube to the base of the main body, where it ignites a 0.8 g black powder charge,[4] launching the mortar shell from the mine and igniting a pyrotechnic delay.
[4] The delay triggers the mine once it has risen to a height of between 0.5 m and 2 m, where it detonates scattering shrapnel.