The Nebelwerfer (German for "smoke launcher", a code name to obscure the real nature of the weapon) was a German towed rocket artillery piece, developed in the 1930s and used in World War II against light infantry targets. It had six 150 mm barrels, from which it fired 75 pound rockets; a full salvo spread over a period of ten seconds. The loud screeching noise of the rounds led U.S. soldiers in the Sicily campaign to nickname the gun the "Screaming Mimi", and "Moaning Minnie". It (as well as the Katyusha) is considered to be the beginning of modern multiple rocket launcher artillery.
The Nebelwerfer 41 was a rocket-launching artillery piece which had six barrels. Each barrel fired a 75 pound 150 mm rocket out to a range of about 6800 metres (about 4.2 miles). The ammunition was known as Wurfgranate 41, German for "rocket grenade". A later version, the Nebelwerfer 42 had five 210 mm barrels and could fire its 250 pound projectiles out to a distance of nearly 8000 metres (about 5 miles). The 210 mm version was equipped with removable internal rails in the tubes to allow for the use of the 150 mm rocket. Both types were towed pieces which were mounted on the modified carriages of a light pre-war anti-tank gun.
The small size and light impact of its weaponry made the Nebelwerfer practically useless against armored targets such as tanks and personnel carriers, but the dense and sustained penetration of its multiple rockets made it extraordinarily lethal when used against unarmored enemy infantry.
After the crew had loaded and aimed the launcher, they would take cover a few metres away and fire the Nebelwerfer by an electric wire. After firing, however, a long streak of smoke could be seen from far away, making the Nebelwerfer an excellent target for counter-artillery fire. It was therefore necessary to relocate the Nebelwerfer as soon as possible after firing.
One way to make up for the Nebelwerfer's shortcomings in mobility was to mount the rocket launching tubes on some sort of motorized tractor, as was the case with the Maultier 42 Panzerwerfer; a lightly armoured half-tracked mount for the weapon. Later in the war cruder (and larger calibred) light metal or even wooden launch racks were devised, in order to cope with the increased frontline requests for the weapon and the growing scarcity of raw materials. The racks could be transported via truck and set up by a small crew which would then swiftly leave the launch site after firing.