Most safes will be supplied key locking. This term means that the safe is secured by a key rather than a combination or digital lock (see other tabs for more info). However, if you would like to have your safe secured by a different type of lock, then this is usually available, but there is almost always an additional cost involved.
Most modern keylocks are 'double bitted' - in other words, there are 2 'bits' on the end which you insert into the keyway (in comparison to standard mortice or 'back door' keys which only have one 'bit'). Being double bitted generally (but not in all cases) gives a greater degree of security in that there are usually more differs available (more different keys to suit that particular lock) so there is almost no chance at all of ever finding 2 keys the same.
Single bitted key |
Double bitted key |

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Most safes can be fitted with a combination lock (or keyless combination lock to give them their full term) and these have always been the main type of lock fitted to safes in countries such as America. However, here in the UK and in most of Europe, we have tended to use keylocks. There are advantages to both - the keylock is easy to use - just stick the key in and turn, whereas combination locks require you to turn the dial left or right to a number, then back again 3 or 4 times, stopping exactly on the right number each time. However, with a combination lock, you can change the combination code whenever you like & as often as you like - there are full instructions to be found on the safe lock info link on the left hand side of the toolbar.
In recent years, the digital locks have really come into common use. More reliable than they were when first offered some years back, digital locks are easy to use and offer the option to change the code very easilly, on a regular basis. As a guide, you can have a safe upgraded to a digital lock from around £200 depending upon the safe and the functions you require.