The Rose 2. 0 Long-Sleeve Baselayer Top uses 100% Responsible Wool Standard-certified merino wool, spun into a midweight fabric that insulates without adding bulk under a shell. Merino's natural odor resistance comes built into the fiber itself, not an added-on finish, so breathability and freshness hold up wash after wash. A regular fit holds the top close to the skin for efficient insulation while leaving room to layer on top. What Our Gearhead(R) Experts Are Saying:"I wore this through three days of ski touring without a wash, and the merino never picked up the sour smell synthetic layers get by day two. It ran warm enough on the skin track that I never had to strip it off, then held heat again once I stopped sweating on the descent."