A combination lock is a lock that is unlocked by dialing a combination. Although it can refer to both mechanical and electronic locks, the term combination lock describes a mechanical lock. Mechanical locks are operated through a dial, which you spin to the left, then right, then left, then right again to open the lock. The dial mechanical locks that we install on our safes will be preset to a unique three number combination. This is a $75 value! Other companies ship the safe without setting the combo, forcing you to contact your local locksmith to set the combo for you. Changing the combination by the user voids our warranty.