Size 63/4 Daisy Mae-boonie style hat this is an unused hat dated 1934. The nap sack is WWII 

The original HBT version was made from light shade cotton herringbone twill and was worn by troops throughout the WWII era especially in the jungles of the south pacific.  It is a very comfortable piece of headgear and offers good protection from the sun with its full circle brim and eyelet vents throughout.  This hat is considered by enthusiasts as the granddaddy of the jungle boonie hat.