Most large institutions or facilities do not want their employees to carry around a large quantity of keys. Similarly, these institutions would like to restrict access based on an individual’s standing, and responsibility, within the establishment. A master key system will allow for different levels of restricted entry. When a master key system is finished there will be a graduated level of access. In the example of a property manager, one tenant’s key (change key) will work on their lock but not on the neighbor’s lock. Employees of the property management company will have a key (sub-master key) that works in all of the tenants locks, and some administrative areas. However, the property manager will have one key (grand master key) that works for all of the locks in that building.

This type of system is great for property management companies that manage multiple buildings. Employees of the company have a grand master key that can work in every building while each building can have it's own sub-master key for the maintenance crew and unique change keys for every tenant.

Master key systems can used with any level of key restriction as well as an Interchangeable Core system (SFIC, LFIC, etc) or High Security key system.