“GY” means Outdoor optical cable for communication,”T” means Filled structure,”A” means Aluminum belt–polyethylene bonding layer. The GYTA cable is a loose tube made of a high-modulus material, which is filled with a 250 μm fiber. And the loose tube is filled with a waterproof compound. The center of the core is a metal reinforced core. For some cores, a layer of polyethylene (PE) is required to be extruded outside the metal reinforced core.