Abstract: A core for making elongate flexible clips having a plastic covering is a length of a flexible metal ribbon having transversely disposed slits cut into the edges of the ribbon. The ribbon includes a generally longitudinal carrier. The slits on opposite sides of the ribbon are longitudinally offset from each other. The core is covered with a plastic material. Thereafter the covered core is bent along one or more axes lying along the length of the core to form a clip. Because of the structure of the core, the clip may be extended longitudinally by tensile forces and resist longitudinal shrinkage in response to the compressive forces applied by the plastic covering.