Even after the lock box with key compartment is opened, the shackle cannot be released unless a separate 3-digit code is entered on the shackle lock inside (that’s the combination you don’t share with other agents!). That prevents this padlock lock box from being removed from the door knob or railing. Sizeable interior holds multiple keys. Black sleeve protects shackle against scratches, and a rubber bumper protects door surfaces. 4-digit padlock lock box has the combination code preset to 0-0-0-0, but you can set your own combination, and change it as you’d like; 4 digits give you more combination options than a 3-digit lockbox.