**Dog Invisible Fences: A Comprehensive Guide to Choosing and Installing the Best System**
Invisible fences are a popular way to contain dogs without the need for a physical fence. They work by transmitting a radio signal from a transmitter placed in the yard to a receiver worn by the dog. When the dog approaches the boundary, the receiver emits a warning tone or shock, deterring the dog from crossing it. Invisible fences can be an effective way to keep dogs safe and secure in their yards, but it's important to choose the right system and install it properly for the best results.