Dogs can hear higher frequencies than humans and this app plays a high pitched sound to stop your dog from barking. Dog whistle app emits sound ranges from 100 to 22,000 Hz. You can adjust the frequency slider for sound pitch customization. The app is really helpful to control and command your pet easily.
Some dog owners believe that the high frequency of a dog whistle might hurt and damage their ears. But no, dog whistles do not hurt or cause damage to the ears.