With a background in self-defense, knifemaker Allen Elishewitz designed the CRKT Grey Tactical Pen Tao 2 to do more than write. If the user of these pens finds themselves in a threatening situation, they can defend themselves with three different elements. The impact crown on the cap is the lowest level, designed to deter attackers, followed by the pointed butt of the pen, and the lethal sharp pen point. When not being used for self-defense, you can depend on the Tao to write under any condition, whether underwater, upside down, or in extreme temperatures. The pen is made of 6061 anodized aluminum, with a stainless steel pocket clip and Fisher Space Pen ball point pen cartridge.