Homemade Wall Stops Roomba And Other Vacuum Tricks | Hackaday
Amazon.com - OYSTERBOY Electrowall Invisible Wall Barrier for iRobot Roomba 600/700/800/900 Series (1)
OEM Virtual Wall Barrier Sensor for iRobot Roomba 500/600/700/800 Series Lot | eBay
Amazon.com - Garbage fighter 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