Abstract: An anti-theft screw part includes an annularly extending recess for engaging an adapter, which as viewed from the outward direction to the inward direction is limited by an outer edge, a bottom, and an inner edge. The screw part is assembled of a main piece and an insert piece. The main piece forms the outer edge, the inner edge is formed by the insert piece. The outer edge is limited by an outer wall surface, located on an outer circle, and by several internal projections, projecting from the outer circle towards the rotational axis up to a first circular line. The inner edge is limited by an inner wall surface, located on an inner circle and limited by several outer projections, projecting from the inner circle towards the exterior up to a second circular line. The first circular line is located completely within the second circular line. The diameter of the second circular line is larger than the diameter of the first circular line.

Abstract: An anti-theft screw part includes an annularly extending recess for engaging an adapter, which as viewed from the outward direction to the inward direction is limited by an outer edge, a bottom, and an inner edge. The screw part is assembled of a main piece and an insert piece. The main piece forms the outer edge, the inner edge is formed by the insert piece. The outer edge is limited by an outer wall surface, located on an outer circle, and by several internal projections, projecting from the outer circle towards the rotational axis up to a first circular line. The inner edge is limited by an inner wall surface, located on an inner circle and limited by several outer projections, projecting from the inner circle towards the exterior up to a second circular line. The first circular line is located completely within of the second circular line. The diameter of the second circular line is larger than the diameter of the first circular line.