The Boonie hat is an extremely common piece of military wear. This garment appeared during the Vietnam War and was introduced by the US military to equip the US Army Special Forces or "Green Berets". The name is a shortened form of "boondocks", which refers to a "remote rural area".

In 1967, Bonnies replaced the "patrol caps" and baseball caps that had been used since World War II.

PERSONAL CLOTHING SYSTEM HAT

The PCS hat is designed for use in operations in open spaces and offers protection from sun and rain. It meets the specifications of the British Army, according to the manufacturer. The Boonie is made of a 50-50 cotton and polyester weave that allows it to breathe, something which is absolutely necessary for an article used in hot environments.

It also has four holes along the perimeter to facilitate the loss of body heat.
In the style of the Australian SASR frill neck or the French Foreign Legion "kepi", there is a piece of material that Velcro's to the back of the Boonie to
protect the wearer from the sun.