2EN5 is a type of glass tube, made from a variety of materials, most notably pyrex. Typically, the walls of the tube are incredibly thin and the diameter is quite small. This makes it popular for all sorts of uses, such as laboratory experiments and the housing of electrical components. For example, the thin walls of the tube allow it to be filled with a variety of gases, or it can be filled with a corrosive liquid. The small diameter of the tube also allows it to fit snugly in tight places, such as inside a circuit board. In addition to its use as a laboratory tool and electrical component housing, 2EN5 tubes can also be used to construct structures, such as small columns or towers.