This headband is called the "Skull Wrap". It has a thick front and a thin back behind the head. So when you put it on it covers most of your head on the frontal/top section holding down your hair. Thus you can place a helmet or cap over it easier, to simply hold down your hair easy. Of course it's sublimation friendly so you can add some SWAG to it!
It comes as a one size fits all.
Material: 88% polyester, 12% spandex
Heatpress at 400 degrees and 25-30 seconds.