Why is this dog repellent so special? -3D Sound if your phone/tablet has stereo speakers(most do) -Adjustable frequency. First of all, using the new 3D Sound technology, the repel sound covers a broader area. Second of all, the other dog repellents use a stock frequency that cant work for all dogs. Every dog is different and choosing the right frequency is important if you want to repel all dogs, not just a few. This app has an adjustable frequency slider that can be in the range of 7500 kHz - 22500 kHz(beyond human hearing) that can chase away most dogs Important Note: Not all frequencies may work with your phone/tablet. Some devices may render artifacts at some high pitched frequencies due to the phone software/manufacturer and/or the devices build in speakers. A safe way to go is around 15000 kHz because most devices can render that and is high pitched enough to repel and chase away most dogs.