For Virtual barriers use invisible to block for robot progress Switch up-Beam mode produces virtual sensor barriers up to 3M / 10ft long Switch down-mode generates circular virtual markers up to 1.2M / 4FT in diameter Dual-mode virtual barriers in beam mode help you intercept the of the to the robot from entering rooms you don ' t allow, and the robot from getting stuck under beds and sofas mode protects the floor ' s babies, toy and pet water bowls mode virtual barrier with on / off switch and low battery for easy identification of use and battery replacement Batteries use 2 pieces AA batteries ( not included) Pay special attention to the invisible wall of the beam mode is generated at the back of the switch, must not be placed to the opposite directiont