The Huntworth Men's Bruggen Heat Boost Performance Fleece-Lined Winter Beanie is our warmest beanie to date. You won't want to leave home without the Bruggen hunting beanie made with Heat Boost graphene technology. Heat Boost is a line of graphene-enhanced material and a pioneer in the next generation of advanced fabrics with new functionalities. Knitting graphene yarn into our Sherpa fabric supercharges this winter beanie with graphene's thermal conductive properties, making a warm material even warmer; 30% warmer. This performance fleece beanie is fully lined with Heat Boost graphene Sherpa for outstanding warmth that you will quickly feel. The sides of this fleece-lined beanie are curved to ensure your ears are covered. A DWR treatment on the exterior makes light moisture bead up and roll off the fabric. Pull on for all day lasting warmth.