This is a new made reproduction of the standard dismounted style campaign hat chinstrap used by US Army Infantry and by the US Marines.  The strap is 1/4 inch wide and 35 inches long.  It is meant to go through the grommets on the hat brim (or through slits made by the owner on earlier style campaign hats without grommets) and can be worn either around the back of the head or under the chin.  These straps are actually a bit long for either application, but that is how originals were made and that is how I copy them.  Apparently most users cut them to fit themselves and in most cases made a new hole.  This style strap came into use around 1912 and was used through WWII
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THIS IS NOT HAT! IF YOU CAN’T COMPREHEND THAT HAVE AN 8-YEAR-OLD ACTUALLY READ THE TITLE AND DESCRIPTION AND HE WILL EXPLAIN IT TO YOU.