Abstract: A hat comprises a flat sheet of flexible but unstretchable self supporting foam of the order of one quarter inch thick. The flat foam sheet is cut to form a forward peak portion and a rearward headband portion with the headband portion having a central opening of a size slightly less than that of the head of the wearer. A plurality of slits extending radially from the hole define a flex portion which can flex upwardly and expand circumferentially to allow the head band to engage around the head of the wearer. More slits are provided at the forward part adjacent the peak to define a concertina type portion which can engage over the forehead of the wearer.