The PetSafe® Indoor Radio Fence Transmitter, a safe and easy-to-use system, effectively keeps your pet out of certain rooms, off furniture, away from trashcans, and more. Simply plug in the unit near the area you want to protect. When your pet gets near the area, his receiver collar (not included) sends a warning beep, followed by a safe, mild static correction. Your pet will quickly learn to avoid the off-limits area. Use this Transmitter with any PetSafe in-ground fence receiver collar (not included; excluding UltraSmart and YardMax systems).