Woolpower Knee High Socks Protection 400The Woolpower Knee High Socks with Flame Resistance (FR) are 400g thick and are made with Woolpower’s Protection 400 fabric combining merino wool with polyamide and aramide to provide Flame Resistance.The Woolpower Knee High Socks have insulating terry knit in the feet and legs and have extra elastic at the top and bottom to provide a comfortable fit.PROTECTION 400 Socks:70% Merino Wool18% Polyamide12% Aramide