Used on Russian submarines, in embassies, and other very high-security applications, this lock was designed to be mounted on a locally-purchased safe, covering the keyhole. It was not designed to defend against forced entry-- the intelligence protected by the lock was only useful if no evidence of entry was left behind. It is designed for dual control-- both a key must be inserted and a combination dialled for the lock to open.
This lock, owned by safe technician Paul Crouwel, is one of four in the world known to exist.
Source (shows much more images): http://ericschmiedl.com/locks/index2.html
