external self-locking flag

例句：

1. 1. The new security system has an external self-locking flag that automatically locks the doors when they are opened.
   新的安全系统有一个外部自锁标志，当门被打开时，它会自动锁定。
2. 2. The company's latest product features an external self-locking flag that prevents unauthorized access.
   该公司的最新产品具有一个外部自锁标志，以防止未经授权的访问。
3. 3. In this case, the external self-locking flag was designed to ensure that only authorized personnel could access the restricted area.
   在这种情况下，外部自锁标志的设计是为了确保只有授权人员可以进入受限制的区域。