When purchasing direct thermal labels, you must prioritize material composition and coating quality. Ensure the labels feature a high-sensitivity thermal coating for crisp printing at high speeds. Key specs include Top-Coated vs. Non-Top-Coated options; top-coated labels offer superior resistance to moisture, oil, and abrasion, making them essential for long-distance shipping. Additionally, verify the adhesive type (Permanent, Removable, or All-Temperature) to ensure it matches your application surface, and confirm the core size (e.g., 1" or 3") is compatible with your specific printer models.