Probably the best thing to do is call Heartland. I'm no expert, but I think that all of the safes that are digital would have to have electricity to make them operate, which would be provided from a battery, so they would have to have a backup system so you could get into them if the battery/s go dead. This would be a key. On my digital safe you enter the combination, and still have to use a key to open it. I always did assume that would make it a little safer, as if a bad guy got the combination, he'd still have to use the key to open the safe. There are so many safes around that could use a variety of things, to be on the "safe" side, I'd call Heartland & get it form the horses mouth. Who knows in mid stream they may have changed safe suppliers & installed different safes during the year's production run. Wouldn't be a bad idea to have your VIN # handy in case they ask for it.