The BBA242 does not have the capability to lock singles keys. However, it does have the capability to lock the entire keypad so that none of the scale painting keys are functional. This can be done by pressing the O/T and é simultaneously for at least 2 seconds. The message "keys locked" appears briefly. To unlock the keypad, press the O/T and simultaneously for at least 2 seconds. The message "keys unlocked" appears briefly. This information can be found in the User's Manual under section 4.3, Locking the Keyboard. This means the automotive paint scale can become a secure part of your scale painting process.