100% Polyester MATERIAL – 100% Polyester . It is a great hat for outdoor activities. It is light weight, breathable and durable. It is easy to fold, convenient to carry and keep in pockets. SIZE – Small/Medium- Inside of hat circumference Approx 21 1/8 – 21 7/8 Measurement is made around the inside of hat, Crown measures approx 4 deep, brim 4 and neck flap 8 long . Large/X-Large- Inside of hat circumference Approx 22 1/4 – 23 Measurement is made around the inside of hat, Crown measures approx 4 deep, brim 4 and neck flap 8 long SUN PROTECTION- It is an excellent sun protection hat. It can protect your neck, ears and face safe from harmful rays. Specially, the surrounding material made by a large shawl sunscreen will protect skin from dust or insects from outdoors. IDEAL FOR OUTDOOR- It is a great hat for all types of outdoor activities. Unisex sun hat is perfect for men and women camping, hiking, Kayaking, gardening, traveling, fishing, boating, hunting, safari, beach, pool, cookouts or sporting events and working outside for all season use. SIZE ADJUSTABLE – Adjustable chin cord holds hat in place and an elastic drawcord with toggle at back of the crown for adjustable fit & size. Includes an internal moisture wicking sweatband.