Teko SIN3RGI Merino Wool Poly Blend Crew Sock Liners 35% M3RINO.XC/35% EVAPOR8/20% Nylon/10% Elastic Made in the USA and Imported Dries fast and is 40% more durable than pure merino SIN3RGI is a blend made from Teko's M3RINO.XC merino wool and polyester manufactured from 100% recycled materials