The first "15 cm NbW 41" rocket launchers were delivered in July 1940, forming three new regiments, the "51st", "52nd" and "53rd Nebelwerfer Regiments", each with three battalions. The "54th Regiment" was formed from the "1st" and "7th Nebelwerfer Battalions". The "Nebel-Lehr Regiment" was formed from the "Nebeltruppen" school in Celle on 29 April 1941 with two battalions, one each with "10 cm NbW 35" mortars and "15 cm NbW 41" rockets. The independent "Nebelwerfer Battalions" retained their mortars with the exception of the 8th, which received rockets before Operation Barbarossa. The only way of differentiating those units equipped with mortars during this period from those with rockets being the "d." or "do." suffix added to the designations of the rocket-equipped units. Beginning in November 1941, the eight Decontamination Battalions were fully equipped with 28/32 cm NbW 41 rockets (some had "sW.G. 40" and "41" launching frames earlier) and reorganized into three "Heavy Werfer Regiments".