What is the significance of the ZN and SR armour designations?

The (ZN) suffix indicates zinc-coated steel wire or tape armour that provides excellent mechanical protection against impact, crushing, and rodent damage, while also offering corrosion resistance. The (SR) mark denotes an additional steel reinforcement variant that further enhances tensile strength and overall ruggedness, making the cable well-suited for direct burial or installations in harsh conditions without compromising flexibility.