iRobot Roomba 385 Virtual Wall

The Virtual Wall Unit allows you to keep Roomba cleaning where you want it.
 Creating an invisible wall up to 2,5 meter long, the Virtual Wall Unit limits Roomba to one room,
one section of a large space, or keeps it out of trouble spots without you lifting a finger.
The Virtual Wall Unit requires two "D" alkaline batteries (not included).
Additional Virtual Wall Units give you more control and more flexibility.