Endura Pro SL II PrimaLoft Socks Hi-Viz Black. They offer optimal insulation during outings on cold days. Made of a mixture of fabrics with PrimaLoft Gold and Silk technology, they help maintain the temperature of the feet in adverse weather conditions. Long cuff edges for extra warmth. It contains a padded area in the toe area and plush on the metatarsal donut. Flexible zone in the arch of the foot.