Amazon.com - 2 Pack Dual Model Virtual Wall Barrier Compatible with iRobot Roomba i, e, s, 900, 800 Series Robots, Replace Part Number: 4636429 -
Amazon.com - 2-Pack Dual Model Virtual Wall Barrier Compatible with iRobot Roomba 500/600/700/800/900/e/i/s Series Robot Vacuum. Compare to Part 4636429 -
iRobot Roomba 500/600/700 Series Auto Virtual Wall Barrier Sensor Lighthouse | eBay
How To Use a Virtual Wall Lighthouse | Roomba® 800 series | iRobot® - YouTube