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. This tends to make the Stinger look more like a tire-pressure gauge-gun than a pen-gun but that is not nearly as snazzy a sell. A neat little metal collar behind the barrel twists around to form a crude but positive active safety device.
The downside of the firearm of course, is its limited practicality. While it could be carried in a shirt pocket conceivably as a self-defense firearm, it would take 2-3 seconds to deploy in even the most optimistic of circumstances. With no sights, it was a point-blank weapon. The fact that it had to be disassembled to reload the single round meant that in almost any circumstance it would be a one-shot wonder.