BM-13 Katyusha multiple rocket launchers are a type of rocket artillery originally built and fielded by the Soviet Union in the World War II. Compared to other types of artillery, such multiple rocket launchers are able to deliver a devastating amount of explosives to an area target more quickly but with lower accuracy and requiring a longer time to reload. These vehicles are fragile compared to conventional artillery guns, but relatively inexpensive and easy to produce. Katyushas of World War II, the first self-propelled artillery mass-produced by the Soviet Union, were usually mounted on trucks.