One size fits all headbands rarely actually "fit all", but the Specialized Thermal Headband gives you fit customization via a simple Velcro® closure at the back that allows for micro adjustments to precisely fit the shape and size of your head. Makes sense, and it makes this a better option for many cyclists and runners that require some breathable thermal protection around their head and ears. The cut accommodates the ear shape for proper coverage and comfort, and though the rear closure adds a little bulk, it is compact enough to work well under most helmet closure systems. With vertical flatlock stitching and a brushed fleece inner surface, your comfort is assured as you confront shoulder season temperatures.