DuckCorp Dico

Found one definition

1.                 From English - German Ding/FreeDict dictionary ver. 1.9-fd1:
                   
   
   
                   
                     
   sheet case /ʃˈiːt kˈeɪs/
   Blechmantel <masc> [techn.]
      Synonyms: sheet cover, sheet covering, metal jacket, steel jacket