Billed as a "revenge product," the Super Sonic Nausea device is the "government model" of the regular Sonic Nausea device that "generates a unique combination of ultra-high frequency soundwaves which soon leads most in its vicinity to queasiness." I think it basically makes a high-pitched, loud, and annoying squeal. It's $99 from law enforcement and military gear supplier Shomer-Tec. From the product page:
Speeches, demonstrations, crowd dynamics, etc. – this device has been used to "influence" more of these than you might expect. Deployed near the podium, you might just have a case of an increasingly un-impressive speaker with diminished sharpness and lacking concentration, or perhaps is even unable to complete his presentation. Or, loitering youths on your property might be enticed to move along with no confrontations necessary.