The head strap can be adjusted from 21.7 to 23.6 inches; one size fits most, and there are adjustable cords and chin straps for a comfortable and snug fit. This fisherman’s hat with neck flap is made of nylon, which is lightweight, quick-drying, and waterproof. The inner sweatband will absorb any excess sweat, and the two side ventilation holes offer added breathability.Perfect for men and women camping, hiking, gardening, fishing, going on safari, exploring, traveling, camping, boating, or other outdoor activities, and working outside.