American soldiers inspect the abandoned German antiaircraft self-propelled units “Wirbelwind”.
Self-propelled anti-aircraft weapon 2 cm Flak auf Pz.IV. “Wirbelwind” (“Whirlwind”) was created as a result of the cooperation of the 12th Panzer Regiment SS and the firm “Ostbau”. A quadruple 20-mm anti-aircraft unit on the panzers of the Panzer IV medium tank was the most effective means of combating low-flying aircraft. In late 1944 – early 1945, Ostbau manufactured 106 such self-propelled anti-aircraft weapons, which were used to arm the anti-aircraft batteries in the tank and motorized divisions of the Wehrmacht and SS, where they were used until the end of World War II.