AVERAGE SIZE fits head circumference of 18″ to 22.5″. Our Wig Grip Band can be worn under any wig, scarf or hat to keep it completely secure. We use a double-sided crushed velvet material, so one side grips to your hair or skin, and the other side adheres to your wig or head covering. Our band is very comfortable to wear and features an adjustable Velcro closure in the back. Never feel your wig or head covering slide around again!