The core of the cable consists of e.g. four insulated optical fibres combined with other elements to form a circular cross section strand. The core is separated by a gap from a tubular section made of glass fibre reinforced plastics. The tubular section consist of two parts with a longitudinal dividing line, which lock together with a snap action. One part is larger than the other, having a longitudinal opening large enough for insertion of the core. The edges are shaped to interlock, and are permanently connected by adhesive on their contact surfaces. The tube may be non circular in section.
