The LawnB LB1200 Spyder battery powered electric robot mower is the world's first robotic mower that does not require a perimeter wire installed in the yard. Lightweight at only 18 lbs, the LB1200 is easy to move from one area to another. Simply unplug the supplied charging cable, place the LB1200 in the yard area to be cut and turn it on. With its patented sensors, it will sense the grass and cut in a slight arch, reversing when it reaches a non grass area (concrete patio or driveway, walkway, mulched areas or any other obstacle it hits with its bump sensors. By having natural or artificial barriers around the perimeter of the yard, the robot will continue to cut for up to 4 hours per charge. When finished, simply connect the robot's charging cable to the robot so it will always be ready to cut again. Designed to maintain a yard and never let the grass get long, simply place the robot in the yard a couple to several times per week. The yard is always trimmed and looking great, with no grass clippings or smelly mess to worry about. And the best thing is you didn't have to push or ride it, enjoying your free time to do the things you enjoy.