The PetSafe Wireless Pet Containment System is a safe and reliable solution to protecting your pet. The wireless containment system transmits a radio signal up to 90 feet in all directions, creating a dome effect. When your pet reaches the boundary zone, marked with the supplied containment area marking flags, the receiver collar gives a warning sound before any correction is given, teaching the dog to stay within the established boundaries. The correction is a safe static correction that will safely deter your pet from leaving the established containment area. Over time your pet will get to know the boundaries and stay within the designated containment area and away from the boundary zone. The wireless pet containment system is portable, allowing you to bring your pet camping or on vacation. The wireless containment system will run all of your dogs with the purchase of additional wireless containment receiver collars. There is no limit to the number of pets that can be added to the PetSafe Wireless Containment System as long as they are wearing the wireless containment receiver collar designed for this product shown below.