I'd just like to chime in that I experienced these things on several occasions in Tokyo, and I'd like to voice my vehement opposition to them. They're not annoying, they're debilitating. Everything mentioned in The Mosquito#Health effects should be taken seriously; it's not simply a “noise”, it’s a pulsing. Something like this: |>-|>-|>-|>-|>-|>-|>-|>-|>-. Bang loud, quickly fades out, and then repeats, probably 2-3 times per second. When I came across them, it went straight to my inner ear and made me disoriented within seconds and physically nauseous within a minute of exposure. The fact that it emits at up to 94 decibels, to me, should make it highly controversial. At 85 dB, OSHA requires hearing protection in a factory. 94 decibels is louder than a lawnmower, and these speakers are usually stuck run above your head on sidewalks. To some of the previous comments in this article, to me, The Mosquito less of an anti-loitering machine and more of a military sound-weapon. It is truly that bad; imagine an instant, pulsing ear infection simply because you walked past a department store that doesn't want kids loitering about. Just my 2 cents.  (talk)(contribs)