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 For Virtual barriers use invisible to block for robot progress 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