A restricted key adds another layer of security for your home or office. With this extra security though, it does make things difficult for yourself.
A restricted key means you can only get a spare key from the manufacturer or from the locksmith that installed the locks. With this extra layer of security, not anyone can make a copy of your key. The Manufacturer or Locksmith is provided with a key that has a unique set of secondary cuts separate from the primary cuts that operate the locking device. Primary cuts are decided by the manufacturer or locksmith like a normal key, which is dependent on your unique situation.