iRobot double virtual walls, simply limit the area to be cleaned.With iRobot"s new Dual Virtual Walls, you can easily limit the movement of your Roomba or Scooba so it can"t access areas you don"t need. The Barrier System virtual wall dual function Virtual Wall gives you more control over where the robot cleans With virtual wall mode, you can decide which rooms the robot should and shouldn"t go into, and halo mode creates a protected area around objects you want to protect These virtual walls are so small they"re almost imperceptible, and they run on two AA batteries per unit (battery not included in this product) There are two modes in which you can determine the position of the cleaning robot. An automatic virtual wall ensures that your robot only cleans in the rooms you want. And Halo Mode won"t let your robot get close to the object you want to protect. Virtual Wall Mode: Longer range to block openings up to 3mThe setup consists of projecting a 3 meter beam of infrared light in a straight line. It"s good for doors. Halo Mode: Forms a circular barrier of 1.2m diameter. The setup produces a 1.2m circular infrared beam around the device. Halo mode creates a circle around the cell that robots will not enter. This can be useful if you have pets. Compatible with Roomba 500 series robots , 600, 700, 800 and 900 The virtual wall dual function virtual barrier is compatible with ROOMBA 500, 600, 700, 800 and 900 series robots. Box contents 2 Virtual Wall Dual Function Virtual Barrier