The threat of tornadoes and other dangers from above is a pretty serious matter for those living in certain areas of the U.S.

So what do you need to keep your family safe in the event of an emergency? A survival bunker could mean the difference between life and death. Here’s what you should have in yours.

Air Ventilation

You won’t survive long underground without oxygen. Installing a reliable air ventilation system in your bunker should be your first priority. You’ll need a system that will last for months and be able to withstand a storm or bomb going off. Calculate how many people will be down in the bunker and for approximately how long, then use that information to determine how much air you’ll use.

Water

Water is more essential for survival than food. Theoretically a person can last three days without water and three weeks without food. Stocking your bunker with water is an area when many people come up short. There’s no telling how long you might be stuck in your bunker so it’s important to have a large cache of water. Opt for jugs or bottles of water that have been treated to last longer than what you might normally find on a grocery store shelf. Remember to switch it out every few months to make sure you have the freshest possible water when trouble arrives.

Food

Perishable goods have no place in a survival bunker. Instead, stock your shelves with canned foods including fruits and vegetables along with long-lasting snacks like MREs. Peanut butter, crackers and canned tuna all have long shelf lives.

First Aid

Even down in a storm shelter accidents can happen so you’ll want to be prepared—small cuts can become infected and there won’t be a doctor around to help you treat it. Put together a first-aid kit to keep down in your bunker that includes pain relievers, antibiotics, antiseptics and plenty of bandages. Be sure to monitor your stash and switch out anything that is nearing its expiration date on a regular basis.

Warm Clothes

It is not warm underground. You’ll need to stock some extra clothes to help get you through the cool nights unless you have a bunker built with some crazy insulation. Pack clothes that he’ll keep your temperature normal like merino wool along with jackets and thick socks. Fashion isn’t really a concern here so be sure to focus on function.

Tools

Depending on how large your bunker is you’ll likely have items down there that could break with constant use. Beds, appliances and lighting could all go haywire and you’ll need to have a way to fix them. While a toolbox might take up too much room in you can still keep a few key items handy, like a screwdriver and pliers, or you could simply have a multitool on hand to help out with repairs.

Batteries

Batteries are going to be your lifeline if your electricity goes out so stock up on them while you can. You’ll need them for flashlights so you can see and for you’re the battery-powered radio you should have on hand to keep track of what’s happening up above.

Important Documents

Keep copies of all of your important documents in a safe down in your shelter. Photo identification, passports, birth certificates, and insurance forms are all a must to make life easier in the aftermath. If your house gets blown away in a tornado or another disaster you’ll want proof on hand that you’re covered.