When evaluating sunhats, prioritize the UPF (Ultraviolet Protection Factor) rating, ideally UPF 50+, which blocks 98% of UV rays. Material composition is critical; for straw hats, look for tightly woven natural fibers like Raffia or Wheat Straw, while for fabric hats, breathable polyester or nylon with moisture-wicking properties is preferred. Ensure the brim width meets your target market's needs—typically at least 3 inches for effective facial protection. Additionally, verify colorfastness to light and perspiration (ISO 105-B02/B04) to prevent fading during outdoor use.