Kevlaris a high strength (5 times that of steel), high modulus (75% of carbon fiber) aramid fiber. Aramid is technically an aromatic polyamide, which is a complex hydrocarbon and a distant cousin of nylon. Kevlaris the most impact resistant fiber on the market, also exhibits the highest tensile strength and highest resistance to damage, vibration and crack propagation. However, Kevlarhas very low compressive strength, so it is recommended that laminates carrying bending or compression loads have carbon fiber incorporated into the laminate to provide adequate stiffness. Kevlaris also hygroscopic, ultra violet sensitive and un-sandable, thus it is not recommended as a sheathing or outer ply of the laminate. Kevlar¨is categorized by weight per sq. yd., available in a cloth weave and sold by the running yard.