10.5 cm Luftminenwerfer M15: German medium mortar
The 10.5 cm Luftminenwerfer M 15 (Pneumatic Trench Mortar) was a medium mortar used by Austria-Hungary in World War I. It was developed by the German firm of Ehrhardt & Sehmer. It was a rigid-recoil, muzzle-loading mortar on a fixed base that used compressed air to propel the mortar bomb to the target. Each cylinder of compressed air lasted for fifteen shots. A notable advantage was that the mortar had no firing signature, unlike conventional mortars with smoke and muzzle flash.