What is their effect (ultrasonic) on human? Was there any study?
The following link may answer to some of the questions.
https://www.researchgate.net/post/Do_ultrasonic_waves_have_any_negative_impact_on_humans2
We may have to think before buying.
What is their effect (ultrasonic) on human? Was there any study?
The following link may answer to some of the questions.
https://www.researchgate.net/post/Do_ultrasonic_waves_have_any_negative_impact_on_humans2
We may have to think before buying.