Abstract: There is disclosed a fastener for clips to be applied to jewelry and costume jewelry products and to clothing accessories, bags and the like. The fastener utilizes a mechanical device actuated through the action of magnets. According to one arrangement, the mobile components of the clip, shaped substantially in the form of small pins that carry out the mechanical fastening, consist of magnets, for which, in each pair of said permanent magnets, there is mutual attraction and therefore closing of the fastening device when they are arranged with the poles opposite, i.e. when one is arranged in such a way that its positive pole faces towards the negative pole of the other.