Is my door suitable for installation? Blair April 02, 2019 10:36 Updated The DB series can be installed on any door between 35 - 50 mm thick. Related articles Do I need to drill holes in my door? Can I keep my existing mechanical deadbolt installation with my Alfred DB series lock? Why is Alfred failing to lock? What tools do I need for a standard installation? Handing Switch Comments 0 comments Please sign in to leave a comment.