The CST fibre optic cable has a metal protect layer of corrugated steel tape between the loose tube and outer cable sheath. All optical fibre is placed into a fiber jelly filled loose tube, and an extra fiber glass yarn inside the CST armor. With large fiber count, a central strength member and will be added among the multi loose tubes. And cable is finished with a PE, LSZH cable sheath. Corrugated steel tape armoured loose cable has excellent performance on tensile strength, crush resistance, water-blocking and rodent proof characteristics.