WHAT DOES IT MEAN?
KEYED ALIKE - This option is used if you want more than one lock to operate with the same key. Locks by different manufacturers cannot be keyed alike.
KEYED TO DIFFER - This option is used if you want all the locks to have different keys. If you only order one lock then it would be keyed to differ by default.
MASTER KEYED - A good example of this is a hotel where all the guests have their own individual keys to their rooms but the hotel manager has one masterkey that will open all the locks.
