A lock-picking set  is one of the best survival tools you can carry in a emergency situation. The ability to open a door without a key will not only save you money, but it could also be the difference between life and death when your only options are to die or be caught.

A pin tumbler lock works on the principle of a central core, or plug, that needs to be rotated in order to open. However, the plug is prevented from turning by a series of pins, which are in pairs — one on top and one below. When a correct key is inserted, the shear line (the split between the driver and key pins) will be manipulated, which allows the plug to turn.

The Art of Lockpicking: Exploring the Tools of the Trade and Their Uses

This is why it’s important to get the right tool for the job: a good lock pick set will be durable, lightweight and easy to use. A standard locksmithing set typically includes two half-diamond picks, which are used to manipulate individual pins; a tension wrench to apply rotational pressure while the picks are in use; and various “rakes,” which are more comprehensive flat pieces meant to sweep across multiple pins at once (the same way that the shear line would be manipulated with a key).

Most quality sets will also include practice locks for you to work with. A good practice lock will be sturdy in construction and ideally be made from materials that resist rust. A hard case to hold your picks and tension wrenches is a nice addition, too, since they are prone to getting lost or damaged if they are not stored and carried properly.