Sotto,

Many of those fire safes that you see in Staples or Office Depot are NOT safes, but fire rated security containers. They aren't inteded to protect against someone trying to break into it, but to protect the contents in a fire. They look secure, but really they're just gypsum boxes with a thin layer sheet metal covering, easily pried open with a prybar or broken with a hammer. Think of them as heavy duty ice chest, that's basically what they are. Even some of the mid-sized ones are still relatively easy to open with regular tools. That's why some safes are TL rated, to protect against this.

It wouldn't really help to heavily armor something that small, when the thief could just pick it up and walk off with it. I believe those containers are best kept inside a much larger, more secure safe to give added protection against heat, not used by themselves. As with any safe, you really need to have it bolted down or secured somehow. Anything less than about 300-400 lbs could easily be moved by a single person with a dolly.