The corrugated steel tape armored duct cable is structured with 250μm fibre in high modulus plastic loose tube, which is filled with water blocking yarns. All loose tubes and fillers are stranded around the central strength member into a compact and circular cable core. Sometimes central strength member is also sheathed with polyethylene (PE) for cable with more fibre count. Outside the loose tube, it is longitudinally covered with a layer of double-sided plastic-coated steel tape (PSP). There is a filling compound between the loose tube and steel tape to protect it from water ingress. The cable is finally completed with a PE sheath outside.