Very suitable for mounting steel angles with 13mm (slot) holes on (lime sand) stone or concrete. Elastic nylon plug suitable for absorbing vibrations, vibrations and (minor) cracking of the base material. Double expansion makes it possible to let the expansion forces work parallel to the edge of the base material, preventing cracking, and the extra large collar of the nylon plug prevents contact corrosion between the attachment and the bolt. The electrolytically galvanized screw is provided with an extra large profiled washer (Ø >20mm) for improved grip on the workpiece. Flexible installation with both hexagon (SW13) and torx (T40)