KD-661 Wireless 1/2/3 Dog Fence . Condition is New open box Description: - This electronic wireless pet fencing system is one of the most reliable, cost-efficient pet containment systems available today. Easy-to-install, rechargeable system is great for any size dog. This wireless pet fence system uses a constant radio signal to create a “stay zone”. The receiver collar worn on your dog picks up the signal. If your dog ventures out of the “safe zone”, which is very rare once he is properly trained, he will hear a warning tone followed by a light static correction which startles your dog but is completely safe and humane.