This is a great starting point for anybody who is considering purchasing a Petsafe Electric Underground Dog Fence. Knowing how it works will make it easier for you to make a decision. In addition, you will also find my Petsafe Fence Selector Guide of great use in speeding your way through the selection process.

• A small indoor radio transmitter box is installed indoors and is plugged into a standard indoor power outlet.
  
• A wire runs from the house and is hidden underground, or attached to a fixed object such as an existing fence, around the boundary of the area that you want to contain your pet in.
  
• The transmitter emits a radio signal that travels along the wire, the wire acts like a large antenna and transmits a signal around the boundary, enclosing the safe area that you have defined.

• The radio signal strength can be adjusted to radiate up to 15 feet from the wire to allow protection of flowerbeds and walkways; 4-6 feet being optimal for training.

• The lightweight receiver worn on your pet's collar has contact points that touch your dog’s neck. The receiver picks up the radio signal being radiated by the wire as your pet nears it.
  
• The receiver first warns him with an audible tone as your dog approaches the boundary warning zone.

• If he continues towards the boundary wire and enters the Static Correction Zone, the receiver will then will give him a brief, harmless extremely mild low level electrical stimulation delivered through the contact points.
  
• This correction is meant to get his attention, but will not cause harm, discouraging him/her from crossing the boundary, until he returns to the Pet Area.
  
• During initial training, white flags are placed at the boundary to offer an additional visual reference to both you and your dog.
  
• Dogs quickly learn to stay away from the perimeter of their invisible safe zone, thus reducing and even eliminating the number of corrections experienced over time.
  
• By spending just 15 minutes a day working with your pet, he can be fully trained in a few days.

 Best of all, since the receiver is just detecting the signal from the wire, you can use as many receivers as you want on the system with one transmitter. That's 1 dog, 10 dogs or a hundred dogs, as long as each pet has its own receiver you can confine it within your boundary.