Helikon-Tex PCS Boonie Hat Policotton Twill MP Camo Head circumference (recommended): S (55-56cm), M (57-58cm), L (59-60cm), XL (61-62cm) 4 air vents on both sides of hat. Detachable neck protector with hook-and-loop Wide reinforced brim. Adjustable chin strap Comfortable and lightweight. Tough and hard wearing Material: 50% Polyester, 50% Cotton