Arms of sound

Arms of the sound were invented in the United States. It can emit a large sound in a certain direction of the straight line.And, it can stop other party's movement.Recently, the small one was made.It might be convenient, when the police arrest the criminal. I agree with it very much.Because it doesn't damage the person. It is moreover because harm is not given to a surrounding person. I want it to come to be used in Japan too.