Safes are made from tough, heavy gauge steel, typically half an inch thick. The safe may have two sheets of hard steel, with ball bearings sandwiched between the two layers. The ball bearings make drilling through the door or sides very difficult.

The door and lock are inherently the weakest points of any safe. Locking the safe door should operate hardened steel or titanium bolts on all four sides. Hinges are internal so that they do not present a weakness to an intruder.

Locks may be key, combination or fingerprint operated. The best safes have combinations of different types of lock and time delays before a lock will open.

Key locks can be picked, even the most complex key operated lock can be picked by an expert. An expert can find a combination code on a rotary combination dials fairly easily. A keypad combination is the best if you have a combination lock. There are no moving parts to go wrong, or to give clues to a safe cracker who is listening to the lock as he or she operates it.

It is important to keep the keypad clean. Dirty or clean keys give clues to anyone trying to get into your safe. Make sure the combination you choose bears no relationship to phone numbers, birth dates or any other data that can be guessed.

The best option is a fingerprint-operated lock. Then you can have absolute confidence that while your fingers are attached to your body that nobody will be able to open your safe without your knowledge.

A fingerprint operated lock combined with a keypad combination lock, or a second fingerprint operated lock set up for a second person provides the best security for guns or valuables

Fire protection is usually built into home safes, with layers of insulating material and expanding door seals that exclude oxygen and prevent combustion of the safe contents.