2) iRobot Roomba Lighthouse Virtual Wall 4000 series 4150 Adjustable Range | eBay
Irobot Roomba Lighthouse / Roomba, TV & Home Appliances, Vacuum Cleaner & Housekeeping on Carousell
Virtual Walls vs Lighthouses – What are the Differences? (Updated!) | The WiredShopper
iRobot on Twitter: "@Linda_FB The Roomba 88 uses Virtual Wall lighthouses. The Scooba can only use Virtual Walls. The Scooba is not compatible with Lighthouses." / Twitter