The walls are about 2 inches thick including the fire protection. Interior is about 30x18x53. The 11 guage steel is a little higher then 12 guage of many others. And is the Sentry is a little bigger, but that may be about it. I've seen nonfire resistant ones in the store, the lock felt a little better, but not much.

No safe will protect against moisture and humidly. You need a heat source of some kind to help stop them. They have an access hole for a plug to go through. Safe heaters can be purchased, but as little as a 25 watt light bulb will also work.