This is a grenade launcher with programmable air-burst ammunition. If the enemy is hiding in trenches you can set it to go off over their holes, if the enemy is hiding behind a wall you can set it to go off behind the wall, etc.. It also has uses in more dynamic firefights, since unlike most grenades it doesn't have a timer, you can fire it into a group of enemy soldiers running at you and set it to go off amongst them. Overall it's a pretty potent weapon.<p>A similar weapon technology was developed by the allies in WWII, it was a radio fused artillery shell called the "VT fuze". It allowed artillery shells to detonate at a specific distance above the ground (or in proximity to an aircraft), instead of on a direct hit. This dramatically increased the effectiveness of artillery (by nearly an order of magnitude), the shells were considered so important that they were only used in situations where they could not be captured and fall into enemy hands.