GYTA33 [Outdoor Optical Cable for Communication with Metal Strengthening Member, Loose-Sheath Stranded Filling, Aluminum-Polyethylene Bonded Inner Sheath, Thin Round Steel Wire Armor, Polyethylene Sheath In the loose tube made of high-modulus plastic and filled with waterproof compound, the center of the cable core is a metal reinforcement. The loose tube (and filler rope) is twisted around the central strength member into a compact and rounded core, the inner gap of the cable core is filled with water blocking compound and the outer aluminum-polyethylene bonded inner sheath is extruded. The thin round steel wire is armored and extruded into a polyethylene outer sheath to form a cable.