The fibers, either of single-mode or multimode type, are positioned in a loose tube made of a high modulus plastic. The tubes are filled with a water-resistant filling compound. A steel wire sometimes sheathed with polyethylene (PE) for cable with high fiber count, locates in the center of core as strength member. Tubes (and fillers) are stranded around the strength member into a compact and circular cable core. An Aluminum Polyethylene Laminate (APL) is applied around the cable core, which is filled with the filling compound to protect it from water ingress. Then the cable core is covered with a thin PE inner sheath. After the CSA is longitudinally applied over the inner sheath, the cable is completed with a PE outer sheath.

• Accurate fiber excess length ensures good performance of tensile strength and temperature
• High strength loose tube that is hydrolysis resistant and special tube filling compound ensure a critical protection of fiber
• Crush resistance and flexibility
• The following measures are taken to ensure the cable watertight:
  Single steel wire used as the central strength member
  Special loose tube filling compound
  Complete cable core filling
  APL moisture barrier
  CSA moisture-proof
  Water-blocking material