However , from September 1943 , the lack of ball bearings ( resulting from USAAF bombing of Schweinfurt ) forced cupolas to be welded on .
A rotating cupola with periscopes was added for the Ausf G. 's commander .
From September 1943 , the lack of ball bearings ( resulting from USAAF bombing of Schweinfurt ) forced cupolas to be welded on .
A rotating cupola with periscopes was added for the Ausf G. 's commander .