10 Must-have Survival Tools You Probably Already Have

Duct Tape
Duct tape can be used to seal almost anything -- except air ducts. suslik83/iStock/Thinkstock

This survival item has so many uses you probably didn't know it was originally intended for keeping moisture out of ammunition boxes during World War II, while still making the boxes easy to open under fire. (Hence its original name of duck tape). But soldiers soon found other uses for it, including patching guns and jeeps [source: Kilmer House].

That versatility makes duct tape good to have around in emergency scenarios. Whether you need to patch a hole, bandage a wound, fashion a belt or make a water cup, duct tape is one of the first household items to turn to when disaster strikes [source: MacWelch]. Just about the only thing you should not use it for is sealing air ducts, because it loses its adhesiveness pretty quickly in heat [source: Preuss]