The light weight design makes the plastic anchor plugs one of the most common anchors used in everyday applications, like hanging brackets, conduit and towel racks. The nylon, or vinyl, design expands to grip the hole to minimize rotation. When a screw is installed into the anchor plugs it expands, exerting force against the material it is installed in. Like all other expansion anchors, these anchors exert the best strength in solid building material, such as concrete.