Power Stretch® fabric sandwiching PrimaLoft® Footwear insulation in a left and right foot anatomical shape put these socks on the cutting edge of warmth technology. Tested above 8,000 meters these socks are as good as it gets.
Sock Height 
Over Calf
 
Sock Content 
72% Polartec, PowerStretch®, 12% Nylon, 10% Primaloft®, 4%Thermolite®, 2% Stretch Nylon with Lycra®
 
Cushion 
Super Heavy