US Army Style Boonie hat aka Bush hat aka Wide brim aka Jungle hat These Boonie hats are great for anyone who has logged many hours outside in the summer. The Loose fit allows air movement inside the hat and the wide brim casts enough shade across the face neck and ears to keep the sun off. This hat is cool and most people learn that after a couple bouts of Sun Stroke. I'm not your Mom but you know she would tell you the same thing. Medium To choose a size, take the measure of the circumference of the head at the height of the forehead Medium = 25 in.