Adjustable Boonie Hat is modeled after the classic military boonie, an essential component of US Army uniforms for over 50 years. This military style cap offers unbeatable sun protection, while four screened side vents on the boonie cap offer optimal cooling airflow, a necessity for outdoor missions. An internal map pocket on this tactical hat is perfect for storing maps and money. military hat is made with a comfortable, durable, and breathable cotton / poly blend. An elastic cord and lock cinches at the crown of this boonie hat, letting you adjust the head size to the perfect fit. Additionally, this military boonie hat features an adjustable chin strap, keeping this tactical cap secure and allowing for an ideal fit. One size fits most (6 3/4 - 7 3/4 hat size), but this tactical boonie hat is fully adjustable to fit most head sizes.