Loose fiber optic cable type U-DQ(BN)(SR)H, 12 fibers, with corrugated steel tube metallic armour, LSZH (Low Smoke Zero Halogen) outer jacket, Euroclass B2ca s1a,d1,a1, 250μm fiber primary coating, longitudinal and transverse water penetration resistant. The corrugated steel tube armour offers a high mechanical protection against rodents and compressive stresses. Optical fibers are kept together inside a thermoplastic tube and filled with water-blocking gel to prevent moisture penetration.