Huacheng's GYXTW is constructed by inserting 250µm optical fibers into a loose tube made of a high-modulus material, which is filled with a water-resistant compound. A layer of double-sided coated plastic steel strip is longitudinally wrapped outside the loose casing. Water-blocking material is added between the steel strip and the loose casing to ensure the compactness and longitudinal water-blocking of the cable. Two parallel steel wires are placed on both sides, and the cable is then formed by extruding a polyethylene sheath.