CookStop was designed so that settings can be locked and tamper-proof. Settings are made using the secure key and cannot be changed without the key itself. A situation in which a locked setting would be used is when an elderly person is having trouble remembering to turn the stove off.
Alternatively, CookStop can be programmed so that the user can make changes to certain settings without the key but not to all of the settings. This is useful if a user needs to control the HOLD time while cooking.
Additional keys must be ordered separately.