None of us would love being obliged to use a gun. But sometimes a gun may be necessary for some security concerns. If you need to carry a gun for some reasons but you are afraid to be noticed with that gun especially when passing security check points, then you should consider having one of those guns designed in form of a standard pen.
Pen design guns are unnoticeable and they offer a very practical use. It has a single bullet clip and a trigger to fire. The working mechanism of such guns are similar to standard ones.