during the production of the sleeve in the deep drawing process in this case the collar is angled inwards and thus forms the abutment for the bent back wire end in accordance with another exemplary embodiment the latching means comprises a depression or dent which is introduced into the sleeve wall the depression can be produced by means of embossing and the aperture can be produced by means of punching for example it has proven to be advantageous to design the depression in the form of a peripheral groove in this case the wire end latches into the groove and thus unintentional withdrawal of the wire is prevented such a groove is likewise produced for example by means of upsetting the sleeve in the longitudinal direction thereof in accordance with this specific method an annular bead is produced on the outer side of the sleeve and the desired annular groove is produced on the inner side by virtue of a movement in the plug in direction the wire or the wire end is inserted into the sleeve and when drawn counter to the plug in direction the wire becomes hooked on the sleeve wall or on the latching means and can only be withdrawn with a large amount of force being exerted or can no longer be withdrawn from the sleeve.