How about double the massive strength?
The best Browning ProSteel safe door is made from multiple layers of steel formed together to provide superior strength, pry resistance and attack protection. The full second panel added to the first is a ket to its outstanding strength. (See illustration for edge view of opened door.)
When all is said and done the door face is 1-5⁄16" thick with all the massive multiple layers of reinforcement. What is the advantage of doing this? A burglars perception of course. Criminals think the door is the best place to attack based on centuries of tradition. And attack they will. But with engineered features like Duo Formed Doors, the door becomes essentially the worst place to attack. At least with a Browning ProSteel safe.
The massiveness of our steel Duro Formed doors will stop them cold should they every give it a try. In the meantime, you get the full peace of mind you want knowing that you have a juggernaut standing between the criminal and your guns. And that's a very good feeling.