Disc locks

 

— the lock, the secret of which consists of a set of discs. The key for such a lock has an oblong shape, with recesses on one edge; when opened, it turns each disc to a certain angle, and the lock opens only when the desired combination is set. Disc locks are considered quite reliable, because it is impossible to open them with a master key, and when you try to drill a lock, the discs will rotate with the drill.