100% polyester Full sunscreen - the ultraviolet protection grade of polyester fabric is UPF 50. 360 brim provides omni-directional shading. The bottom of the brim is large to help reduce glare. Keep cool - the mesh along the hat crown promotes air circulation and keeps the head cool. The waterproof surface is supplemented with moisture absorption and perspiration belt to absorb moisture and perspiration. Size - adjustable size for 22 - 23 7 / 8 inches (about 55.9 - 60.9 cm) (7-7 5 / 8) head circumference, wide brim 5.9 inches (about 15.0 cm), net weight 0.12 kg, height 3.9 inches (about 9.9 cm) Adjustable chin pull cord - this breathable hat also has a jaw strap to keep it firm when the wind comes. Lightweight - it can be flattened and floated, no matter where you go when you're exploring outdoors. Provide comprehensive sun protection for anglers and outdoor activities.