Aramid yarn or Kevlar layer in a fiber optic cable provides strength and protection. Aramid yarn is a strong and lightweight synthetic fiber often used in applications requiring high strength, like bulletproof vests. Placed around the outside of the cable, it offers tensile strength, safeguarding the cable from damage caused by bending or twisting. The yarn also protects the cable from moisture and other environmental factors. Its benefits include superior strength, lightweight nature, and resistance to damage, making it an essential component for durable and reliable fiber optic cables.