Functioning - The SXS is suitable for push-through installation. Screwing in the CO-NA screw causes the SXS to expand in four directions and anchor into the building material. - When a crack forms in the concrete, the cones of the screw actively expand, thus increasing the expansion effect and the holding force of the plug. - Countersunk head screws are recommended for the installation of timber constructions in the case of metal constructions, use plugs with a wide sleeve rim and a moulded washer on the screw, which also features an integrated hexagon socket.