The Thermowave Arctic men's long-sleeve base layer is designed for uncompromising protection and superior thermal comfort in the most demanding winter conditions. Featuring an exceptionally dense fabric weight of 265 g/m², it is the perfect base layer for winter expeditions, mountaineering, ski touring, or hunting in sub-zero temperatures. Despite its premium insulating performance, it remains lightweight and compact, weighing only around 260 g, while also offering reliable sun protection with a UPF 40 rating.

Made from a refined blend of 95% merino wool and 5% elastane (Lycra®), it combines the unmatched natural properties of wool with exceptional elasticity. A standout feature of the Arctic collection is the softly brushed interior, which creates a cozy feel against the skin and tiny air pockets that trap warmth. Fine merino fibers are naturally breathable, effectively wick moisture away from the body, and offer antibacterial properties to prevent unpleasant odors even during multi-day tours.

An ergonomic next-to-skin fit follows the body's natural movement for unrestricted mobility, while the dropped back hem reliably shields the sensitive lumbar area from cold drafts. Flatlock seams effectively prevent chafing under backpack straps or layering garments, making this shirt exceptionally comfortable for all-day wear. Thermowave Arctic is the ultimate choice for anyone seeking maximum warmth and reliability in arctic cold.