http://harpers.org/archive/2003/02/0079475
 

When killing just won't do

From "Nonlethal Weapons: Terms and References," a report published by the United States Air Force Institute for National Security Studies. According to the report's introduction, many of the weapons are still in the proposal stage.

Acoustic

Acoustic Bullets: High-power, very low-frequency waves emitted from one- to two-meter antenna dishes. Results in blunt-object trauma. Effects range from discomfort to death.

Curdler Unit: A device that is plugged into a sound system to produce a shrill, shrieking, blatting noise. It is used to irritate and disperse rioters and has a decibel range just below that of the danger level to the human ear. It is used in night operations to produce a "voodoo" effect and breaks up chanting, singing, and clapping.