The structure of GYXTW optical cable is to sheath 125μm fiber into a high modulus loose tube, which is filled with water-resistant compound. The Loose tube is wrapped with a layer of double-side plastic coated steel tape(PSP) longitudinally. The water blocking material is filled between PSP and the loose tube to ensure the compactness and longitudinal water blocking. Two parallel steel wires are placed at the two sides of the steel tape. The cable is completed with a polyethylene (PE) sheath.