Polartec174 Thermal Pro174 fleece is not only warm, lightweight and highly breathable, it39s extremely durable and highly resistant to pilling Distinctive ribbon accent sets this style apart V Notch Adjuster with cordlock looks great and ensures a perfect fit Designed, tested and manufactured in the USA. Lifetime warranty One size fits most TrailHeads Peak Base Camp Hats and Beanies provide a great blend of fashion and function featuring Polartec174 Thermal Pro174 double sided fleece with the exclusive V Notch Adjuster in back to accommodate a wide range of head sizes. These hats are made of Polartec174 Thermal Pro174 fleece which has a unique soft surface texture and 34warmth without weight34. Polartec174 Thermal Pro174 fabrics are the most visually dynamic and technically advanced of the Polartec174 insulation fabrics. The 100% polyester velour, pebbled, or shearling surfaces of the Polartec Thermal fleece create air pockets that trap air and retain body heat, providing outstanding warmth without weight. These fabrics offer excellent breathability and dry quickly.