The triggering element (1) consists of a cylindrical part (2) with very thin wall (3) and a upper plug (4) as well as a lower plug (5). The upper plug has a flat bottom (11) with considerable material thickening of the head part. The lower plug consists of a conical part (8) with a transition (9) into the cylindrical part. The material thickenings on both plug ends are orientated towards the inside of the cylindrical part. The transition surface (9) encloses with the axis (10) a specified angle (alpha).
