Whereas mechanical locks are difficult to operate, new electronic safe locks use "smart" dials or push buttons. Combinations of mechanical locks can be difficult to remember, but some electronic locks offer alphanumeric keypads that allow users to compose combinations from easily remembered words instead of strings of numbers. The required periodic changes in the combinations of mechanical locks often result in lockouts due to errors. Electronic safe locks feature user-changeability without a high risk of lockout-causing errors. A mechanical lock has but one combination, and the greater the number of people who know the combination, the less control and accountability there is. One of the new breed of electronic locks is a multifunction smart lock that accommodates multiple user codes that are selectable, changeable, and deletable by people who have been assigned higher level master-user codes. The multiple functions of one of the new electronic locks permits its use on multiple safes under centralized control. Other advantages of electronic locks are their imperviousness to conventional manipulation techniques and the hidden placement of the lock itself which defeats drilling efforts.