Additional Virtual Wall Lighthouse.
For use with the Professional Roomba (76818) and the Seven Day Programmable Robotic Vacuum (74520). Projects infrared beams that confine the vacuum to one room and, when the unit finishes cleaning the floor, allow it to move on to another room. Requires two C batteries. 9 1/2" H x 3 1/2" W x 4" D. (4 1/2 lbs.)