For high-intensity activity in cold weather, choose the icebreaker Men's 200 Zone Knit Long Sleeve Crew base layer. Made with 100% Merino wool, it naturally resists odours & feels incredibly soft. icebreaker’s Zone Knit body mapping technologyis designed to actively regulate your body temperature by increasing ventilation where you need it most. Comfortable to layer, it boasts flatlock seams for reduced friction & thumb loops to prevent sleeve bunching. The gusseted underarms ensure complete mobility.