This illustration shows the multiple levels of a commercial grade master key system

In a master key system, each lock has its own key that opens only that particular door. There also exists a "master key" that opens all the locks in the system. As you can see above there can be multiple levels of master keys depending on your needs. Master key systems are usually found in commercial environments, but can be applied in a residential situation as well. They are appropriate in any situation where you want to grant access to some doors and restrict access to others. 

 Since the locks only have to be re-pinned, integrating a master key system into your current hardware is surprisingly affordable. Not only do we design and implement new master key systems, but we can service and expand your existing system as well. If you lost the charts for your current master key system we can make new ones for you.