The bers, 250μm, are positioned in a loose tube made of a high modulus plastic. The tubes are lled with a water-resistant lling compound.A steel wire locates in the center of core as a metallic strength member. The tubes (and llers) are stranded around the strength member into a compact and circular cable core.After an Aluminum Polyethylene Laminate (APL) moisture battier is applied around the cable core, this part of cable accompanied with the stranded wires as the supporting part are completed with a polyethylene (PE) sheath to be gure 8 structure.