The BM-13, commonly known as the "Katyusha," is a Soviet rocket launcher that was first used during World War II. It is mounted on a truck chassis, allowing for mobility and quick deployment. The BM-13 fires multiple rockets in rapid succession, making it effective for saturating enemy positions with explosive firepower. The design of the BM-13 includes a series of launch tubes that can hold multiple rockets, typically 132 mm in diameter. Its ability to deliver a large volume of fire quickly made it a valuable asset for the Soviet Army and contributed to its reputation as a fearsome weapon on the battlefield.