Lorpen Hunting Extreme Primaloft Socks 75% Primaloft yarn/ 15% Nylon/ 10% Lycra Imported PrimaLoft Yarn is comprised of 50% Merino Wool and 50% PrimaLoft Insulating Fibers to deliver extraordinary wicking and drying properties High Lycra content keeps the socks wrinkle free and in place SBS (Stitch by Stitch) toe seam ensures no rubbing or irritation in the boot Double reinforced toe and heel. Machine wash and dry.