Kevlar
Kevlar is a durable synthetic plastic fiber that has high strength and elasticity, is stretchable, acid resistant and fire resistant.
Kevlar is used as an aramid yarn strain relief material in fiber optic cables, surrounding the glass fiber. The plastic fiber is inside the protective plastic tube along with the glass fiber. Kevlar is also used in loudspeakers because of its high elasticity. Kevlar is a registered trademark of Dupont.