Bolt locks are locks that block or unblock the operations of switches
and controls.
The key on the left is blocked with the bolt visible. In order to retrieve this key,
the one on the right has to be inserted and turned, pushing in the bolt
and so releasing the first key. The second key (the one on the right), is now
blocked and will remain so until the operation is carried out in reverse.
Article code: V55.SB12