Operates only one lock, or one group of keyed alike locks. The more powerful key at the top is called the master key.
Master key lock systems solve the problem of needing a separate key for every point of entry. By using a single master key, you can consolidate them all into one. In addition to making things simpler for you, other benefits include:
Security- Having fewer keys to misplace makes a master key lock system more secure.
Scalability- New construction can use the same master key lock system.
Lockout Protection- You will always have a key with a backup with a master key lock system.
Access Control System- A master key lock system can act as a simple access control system.