Glass fiber offers many design advantages, especially considering its relatively modest cost. It is much stronger than steel in tensile strength, and almost as strong as industrial-grade carbon fiber. Its high elongation (roughly 5% strain-to-failure for E-glass, compared to carbon at 1.5-2.0%) enables structures to absorb greater impacts or abrasive forces when paired with high-elon- gation resins. In fiberglass composites, the coefficient of thermal expansion can be tailored to be closer to that of aluminum and steel, making it a good candidate for metal/composite structures that see fluctuations in temperature. And the molecular structure of the glass itself makes it more amenable to various coupling agents and sizings. This improves glass fiber’s adhesion to a broad variety of polymers.