Ultrasonic frequencies do not travel between walls. Do not place your phone behind couches, curtains or other "soft" items which will absorb rather than reflect the ultrasonic frequencies.
The application might not work in certain environments where it is moist or loud environments (since it will block the signal). We advice the app to be active in the foreground for maximum repellent. If the app is run in the background it will run in low power mode (the signal will activate at specifically calculated intervals). In less optimal environments the application might not work the first try.
Warning: It is possible to adjust the frequency of the application, but it is not advised to do so. It can affect other animals (like your dogs and cats) if you do so. If the default settings disturbs your pet, lower the frequency. Normally the default setting will be optimal.