PetSafeWireless Containment System - portable, no wores to bury. Just plug in the transmitter into an electrical outlet close to the area where you wany to contain your pet. The traansmitter communicates with your dog's receiver collar and helps keep him in the designated area. The system is portable, so you can bring it along with you. An unlimited number of pets can be added to the system as long as they wear a PetSafe Collar. The system was NEVER used! And includes Transmitter with power adapter, received collar for neck sizes 6 to 28", operating and tragining guide, 6v lithium battery, 50 training flags, test light tool.