Selecting carbon fiber requires matching the tensile strength and modulus to your specific needs. For aerospace and high-end sporting goods, High Modulus (HM) fiber is essential for stiffness, while Standard Modulus (SM) is the most cost-effective for automotive and general industrial reinforcement. Always verify the tow size (e.g., 3K, 6K, 12K); smaller tows like 3K offer better aesthetic finishes for consumer goods, whereas large tows (24K+) are preferred for structural civil engineering to reduce labor costs.