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Mountain Equipment says:
A superfast drying action layer that combines warmth and weather protection for the most demanding climbing and mountaineering.
Balancing the moisture transfer required for running up exposed ice fields with the durability needed for rock climbing in the high mountains. The specially developed Octayarn Warp-knit lining offers insulation you can move fast in combined with rapid drying that will be appreciated on one day sprints and multi-day missions alike.