Wikipedia
Panzerwerfer
The German Panzerwerfer is one of two different types of half-tracked multiple rocket launchers employed by Nazi Germany during the Second World War. The two self-propelled artillery vehicles are the 15 cm Panzerwerfer 42 auf Selbstfahrlafette Sd.Kfz.4/1 (based on the Opel Maultier, or "mule", half-track) and 15 cm Panzerwerfer 42 auf Schwerer Wehrmachtsschlepper (or Panzerwerfer auf SWS).