When sourcing jackets in bulk, the fabric composition and GSM (Grams per Square Meter) are the primary indicators of quality. For outdoor or functional jackets, prioritize waterproof ratings (e.g., 5,000mm to 10,000mm) and breathability (MVP ratings). Ensure the use of branded hardware like YKK zippers, as zipper failure is the most common reason for returns. For insulated jackets, verify the fill power of down or the weight of synthetic insulation to ensure thermal performance meets your target market's climate needs.