| 摘要 |
A movable closure having a fixed cylindrical outer shell and a revolving inner s hell, wherein each shell comprises two openings and the openings in the outer shell can be closed or opened by suit able rotation of the inner shell, can serve as a high security door or window for use in buildings. By providing a n additional conventional closure in the outer shell, the function and appearance of a conventional closur e can also be obtained.
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