Length of the Stinger when in pen mode is just under 6-inches. This is the same as a normal Bic-style disposable pen, but is closer to the thickness of a sharpie-style marker. At 5-ounces, it was heavy for a pen, but still less than an 8-ounce single-shot Butler derringer. The case, 2-inch barrel, and internal parts are all made of steel. No aluminum, pot metal, or plastics -err I mean polymers were used in the construction.

http://www.guns.com/2012/10/30/stinger-pen-gun/