Comfort starts from the inside, out. Naturally insulating, moisture wicking and antimicrobial – Merino Wool andperformance yarns wrap your feet in cushioned comfort. 38% Merino content, the most in the sock line-up, boosts the Boot Sock Thermal insulating power for the coldest, longest days on deck. High-power instep elastic locks in a blister-free fit. Nylon reinforcement yarns at heel and toe boost durability. Were so confident in our USA made, sustainably sourced socks that were putting a lifetime warranty behind them. If your socks fail, well replace them, no questions asked.