From Wikipedia ..... A cork hat is a type of headgear with cork strung from the brim, to ward off insects. Traditionally worn by jackaroos and swagmen in the blow-fly infested Australian outback,[1] the cork hat has become part of the stereotypical representation of the Australian ocker.[2] The shape and material of a cork hats vary, though typically they are shaped like slouch hat. Pieces of cork, often shaped as bottle stoppers, are hung on string from the brim of the hat. The low density of cork means a number of pieces may hang from a hat without significantly increasing the weight. Movement of the head causes the corks to swing, discouraging insects from swarming around the wearer's head.