Door strengthening /Other/ASSAOEM/Lock%20guide%20by%20ASSA%20OEM/D%c3%b6rrf%c3%b6rst%c3%a4rkningsbeh%c3%b6r%20524x224.jpg Door strengtheners is included as a component of an approved lock and means that the door is reinforced with plates or escutcheons on both sides of the door, close to the lock. Door strengtheners fasten with through-screws. The screws should not be able to remove from the outside.These door strengtheners can be covered with decorative plates in the same finish as the handles on the door. There is no guarantee that your door is prepared for Door strengthening, and this requires a professional for the installation. Therefore it is important that you contact your door supplier for verification before, so your door warranty isn't affected due to the retrofitting of door strengthenings.