eg of aluminium or stainless steel on the one side of the fastener means a primer layer 2 is arranged which is bonded to the fastener means 1 through a first hardening a material which is weldable by high frequency welding is arranged on top of the primer layer and is bonded thereto by means of a second hardening for building up a connecting layer 3 that connecting layer which is weldable by high frequency welding is constituted by a material which is selected from among polyvinyl chloride pvc polyurethane pu or from among said plastics strengthened by reinforcements conveniently a glass fibre reinforcement said connecting layer is conveniently provided through coating of the primer layer 2 with a layer of polyvinyl chloride or polyurethane with or without reinforcement which layer is bonded to the primer layer through a second hardening in fig2 reference numeral 4 is used to designate a construction part of a material which is weldable by high frequency welding fig2 shows an element according to according to fig1 connected to the construction part 4 the prerequisite for that connection to take place by high frequency welding is that the same type of polymer partakes in both the connecting layer 3 and the construction part 4 ie if the connecting layer is.