Your Zero Halliburton lock restricts access to valuable or sensitive documents stored inside your briefcase. The Zero Halliburton company makes a range of locking briefcases -- one of which stored lunar rock samples during the Apollo missions -- that use a special three-digit locking system. Resetting the combination on your Zero Halliburton briefcase ensures your documents remain safe after the code is discovered. For security reasons, you need the existing combination to reset your briefcase lock.

Turn each of the dials so the three digits of your combination read left to right. The factory default code is "000" if you are setting your lock for the first time; otherwise turn the dials to your existing combination. Open the briefcase.

Look behind the lock inside the briefcase; there is a switch. Slide the switch to the left, then upward. The briefcase lock enters configuration mode.

Spin the dials on the front of the briefcase to reflect your new combination, left to right. For example: "312."

Move the switch behind the lock back to its original position by moving it up and to the right. The lock exits configuration mode.

Jumble the dials; your new combination works immediately. Write it down in a safe location in case you forget in future.