Disclaimer: “Fire proof file cabinet” is a commonly used misnomer. They should be called “fire resistant files” or “fire files” because they are not technically fire proof. Most have a one hour fire rating while a few are rated for two hours.
Many people are not aware that there is such a thing as a fire file. When they have massive amounts of important documents that need to be protected from fire, folks usually buy a fire safe for storage. But few safes have drawers, so organization of papers is difficult. Fire files make organizing easy and efficient. They come in 2, 3 and 4 drawer units, for either letter or legal size papers. Vertical and lateral styles are available. 90% have key locks, and combination locks are optional upgrades. New units will run $1000 to $3000 so you might want to find used ones.
A good safe is harder to break into than a fire file. However, if fire protection and organization of papers are the key issues, then get a fire file.