he Wurfrahmen 40 was a German World War II artillery unit. It combined the SdKfz 251 halftrack with rocket artillery to form a more mobile, hardened artillery piece than the Nebelwerfer. It was nicknamed Stuka zu Fuss (Stuka on Foot or Walking Stuka) and "Bellowing Cow". The weapon consisted of several frames attached to the SdKfz 251 holding 300 mm explosive rockets. 280 mm explosive and 320 mm incendiary rockets were also used. As with all contemporary rocket artillery, the rockets tended to be rather inaccurate and therefore a large quantity of them were concentrated on a target whenever possible.