The Bilontec B-HC anchors are made of a metal sleeve and a metal expansion cone. By screwing in a metal normal metric screw with necessary length, not delivered with the product, the expansion cone is pulled into the sleeve. Therefore, the sleeve expands outside the concrete in the hollow area of the hollow prestressed concrete slab. To ensure that the anchor is expanded properly and the expansion cone is pulled into the sleeve sufficient torque moment must be applied on the anchor.