Designed with 65% cotton and 35% Polyester. Ripstop material for wear and tear damage. Adjustable chin strap to accommodate any head size. Oversized brim to protect from sunlight. Interior pocket to carry maps or notes. Brass screen vents provides air flow. Sewin webbing around crown. In the Box 1X Boonie Hat Specifications: California Proposition 65 Warning: Cancer and Reproductive Harm - www.P65Warnings.ca.gov