The Duopower offers very good holding values due to 2 components: The gray component made of high-quality polyamide automatically activates the optimum functional principle (spreading, folding, knotting) for the best hold, depending on the building material. The expansion wings of the red component support secure spreading and provide additional safety to the gray component. Easy screwing in of the screw and correct pulling at the end. No overtightening of the screw. The edge formed on the dowel prevents the dowel from slipping into the drill hole.