This head strap is not like the one shown in the picture. The one I received was a strip of material with slots for the ears and velcro at the ends which attached at top of the head. It does have somewhat of a chin strap that keeps the mouth closed. The slots for the ears keep the strap from sliding off your head but it rubs and irritates the ears while you sleep. The picture makes the strap look like it runs behind the head for stability but in actuality it uses the ear slots..