Abstract: The means for storing material in filamentary form comprises basically a tension member consisting of elastic material, e.g. plastics or rubber, which is fitted into the bobbin of the storage system and serves to support components situated inside the bobbin. Such components may, for example, be retaining magnets for securing the bobbin against rotation, or a reflective strip for a photoelectric cell system for controlling the axial length of the yarn package formed on the bobbin. The tension member is secured in the bobbin by means of noses or ribs and associated recesses. The components to be fitted in the bobbin, e.g. magnets or reflective strips, are also secured by suitable projections on the tension member or resilient tabs. The tension member and the components to be mounted in the bobbin can readily be removed therefrom.