This is a rare, Hanoi-made-for-the-Viet Cong, black boonie hat. The material is cotton poplin. This is the typical material used for Hanoi made uniforms. The construction is standard six panel crown and six panel interior with circular sewing on the brim. This one does NOT have the plastic lining between the interior and exterior crown. This too is typical for Hanoi made boonie hats. Only the ChiCom made boonie hats had the hidden plastic inner-lining. Also, this has three streel grommets on each side. As you can see, these have aged over the past six decades and have a very nice patina to them. Size is about 6 1/2. Black boonie hats are surprisingly uncommon given the fact that black pajamas were worn by some many Viet Cong.