The PetSafe Little Dog In-Ground Fence allows little dogs have the freedom to play while staying safely in their yard. Simply bury the wire where you wish your boundary to be. Your dog wears a receiver collar that detects the radio signal travelling through the wire. When your dog approaches the boundary, the receiver will issue a warning tone. If your dog ignores the tone and tries to cross the boundary, he will receive a safe, but startling, static correction. While harmless, the correction will persuade him to stay in the established containment area. With 4 levels of static correction plus a tone only mode, you will be able to select the right level for your dog.