Katyusha multiple rocket launchers are a type of rocket artillery first built and fielded by the Soviet Union in World War II. Multiple rocket launchers such as these deliver explosives to a target area more quickly than conventional artillery, but with lower accuracy and requiring a longer time to reload. They are fragile compared to artillery guns, but are inexpensive and easy to produce.
Katyushas of World War II, were usually mounted on trucks. This mobility gave the Katyusha another advantage: being able to deliver a large blow all at once, and then move before being located and attacked with counter-battery fire.
This variant BM-13HMM uses postwar chassis ZIL-131