The warmest socks I have ever worn are a blend of merino wool and possom fur. I spent almost 35 bucks on one pair and I thought that was totally outrageous, but they are worth every penny, they are naturally wicking, the merino keeps you warm and the possom is so soft. But after about 6 weeks of wearing and washing, a huge hole appeared in one toe. On the wrapper of the socks was a website so through that site I sent an email to the manufacturer and told them I loved the socks but didn’t feel they should wear out so quickly. They wrote back and basically told me it was my tough luck, they don’t guarantee their socks. I was going to buy more but I won’t do business with them any more after that. Too bad, they are wonderful socks, except for the hole. (Does anyone know how to darn socks?)