Place the Outdoor Pet Barrier in any area you want your pet to avoid. The Barrier Transmitter, disguised as a rock in your landscape, sends a circular radio signal to your pet's Receiver Collar. When your pet enters the Barrier Area, he'll hear audible tones from the Receiver Collar followed by a safe, progressive static stimulation. The stimulation is delivered through the Contact Points of the collar that touch his neck. He'll quickly associate the stimulation with the area you've declared off-limits. Add an unlimited number of extra barriers or collars for any number of pets and protected areas.