This weapon is used by some assassins. It's primary purpose is to provide a covert weapon that can be used in situations where the assassin will be searched (patted down) and all weaponry will be removed.
Note: actual size may vary depending on the assassin. Masters directing assassins using this weapon may want to select those with the largest noses so that they may be fitted with bigger darts. Beware the large nosed assassin. He may be using the space in his nose for weapons storage.
The design is quite important. You need to be able to exhale without releasing the dart until you're ready. If the pressure builds beyond a certain point you want the dart to fly by breaking the barrier holding it in place. Also, you want to prevent the dart from being inhaled. A filter and gasket provide this functionality. The filter on the business end breaks when the pressure reaches a certain point. The gasket simply keep the dart from being sucked backwards into the nasal cavity.
To fire it you plug the opposite nostril and exhale with great strength. This breaks the holding filter and allows the dart to fly out. To aim, you'll have to angle your nostrils in the direction you want the dart to target. Do keep your hand out of the way, and try not to pick your nose when using this weapon.
The dart has an extremely short range - approximately eight feet. The toxin delivered must be potent since there won't be much of it. And using this weapon effectively would require some training and practice. Assassins using this weapon should select a poison for it from the existing list of toxins.
Recent emergencies in the US may have you thinking about emergency preparedness. Get your survival gear ready for the next event.