These drywall anchors and screws are great for hanging ledges on fairly soft drywall. Plastic drywall anchors prevent the anchor from turning in the hole during installation. The slit of the ribbed anchor bolt expands to the opposite sides when the screw is tightened to increase the holding force, and the anti-rotation structure design of the expansion sleeve prevents the screw from rotating with the drilling hole when the screw is tightened.