The BM-21 "Grad" is a 122 mm mobile rocket launcher designed by the Soviet Union and first put into service in 1963 to replace the older BM-14 system, the 140 mm BM-21 "Grad" is a 6x6 rocket launcher mounted on the Ural-375D truck, which provides high-speed rocket launching on both roads and off-road routes, and later on the Ural-4320 6x6 rocket launcher, which is a newly developed system, consisting of 40 rocket launches arranged in a square-shaped pattern, with multiple rocket launches taking up to 20 seconds with a rocket launcher mounted on a single rocket in the first round.