Constructed to wick moisture while providing insulation, the Ninjaclava(TM) fits perfectly under a ski helmet so they can enjoy the winter weather without feeling its harsh effects. 54% nylon, 41% polyester, 5% spandex. Soft Motion Fleece(TM) fabric provides insulation and moisture-wicking protection. 1.7 oz. total weight. Flat seam construction to eliminate irritation. Hood hinges back to vent excess heat.