Several common cable outer sheath materials are PVC, PE, LSZH, AT and rodent-proof sheath materials. It has good performances, good chemical resistance and weathering resistance, low cost, low flammability, and can meet the. The outer sheath material of an indoor fiber optic cable is the protective layer that surrounds the cable and provides mechanical protection and environmental resistance. PE sheath. Cable sheathing is the outermost layer of a cable that protects it from physical damage, moisture, and chemical exposure.