The 2-pack of Dual Mode Virtual Wall® Barriers gives you greater control over where your robot cleans. Virtual Wall Mode keeps your robot in the rooms you want cleaned and out of the ones you dont away from items you want to protect.  Use a Dual Mode Virtual Wall Barrier to manage where your robot cleans. Virtual Wall Mode blocks openings of up to 10 feet, keeping Roomba in the rooms you want dont. Halo Mode creates a 4-foot diameter keep out zone around items you want to protect. Compatible with Roomba 500, 600, 700, 800 and 900 Series Robots Requires 4 x AA Batteries