When sourcing thread yarn, the material composition (e.g., 100% Spun Polyester, High Tenacity Nylon, or Cotton) is the primary determinant of performance. You must verify the Yarn Count (e.g., 20s/2, 40s/2, 60s/3), as this indicates the thickness and strength; a higher ply usually offers better tensile strength. For industrial applications, ensure the yarn has high colorfastness (Grade 4 or above) to prevent bleeding during washing and low shrinkage (less than 1%) to maintain garment shape. Additionally, check for silicone lubrication levels, which reduce friction and prevent thread breakage during high-speed sewing.