Mortice Locks and Conversion Sets Lever mortice locks fit into the edge of a door and are operated by a key and lever system. Locks are available with between 2 and 5 levers (2 and 3 lever are recommended for internal doors, 4 and 5 lever are recommended for external doors), with 5 lever products offering the most security. The UNION name has been synonymous with mortice locks for over one hundred and seventy years. Today UNION offer a comprehensive range for both architectural specification and residential use. This include those which have been accredited with the South African Bureau of standards and have been specifically designed for high security applications on external doors. There are also standard variants for internal doors. The majority of mortice locks included in this section are manufactured in South Africa. Other specialized locks have been sourced from ASSA ABLOY Group companies worldwide.