THORLO'S Extreme Cold Over Calf Mountaineering Socks - Navy (EU 43-47)

When you are climbing at 5,000 metres in winter, the thin air isn't the only thing testing you — the cold seeping through your boots can stop an ascent in its tracks. These THORLO'S Extreme Cold Over Calf socks are built for exactly that moment. With maximum cushioning and an over-calf height, they provide a protective barrier against snow, cold, and the wear-and-tear of technical terrain. The THOR•LON® acrylic blend works relentlessly to wick moisture away, keeping your feet dry and warm from the first step to the summit.

Key specifications

• Product type: Mountaineering socks
• Sock height: Over calf (OC)
• Cushioning: Maximum cushioning
• Thermal rating: Extreme cold
• Material composition: 85% THOR•LON® acrylic, 13% nylon, 2% spandex
• Size: EU 43–47 (US men's 10.5–12, US women's 12–13.5)
• Colour: Navy
• Country of origin: USA

Why choose it

THOR•LON® is a proprietary acrylic fibre engineered to wick moisture efficiently, and in this extreme-cold model it is combined with a dense terry loop for maximum thermal performance. The flat knit toe seam eliminates friction and prevents blisters during long descents. Integrated arch support reduces foot fatigue, while reinforced heel and toe areas hold up to heavy use on rock and ice. Ventilation panels remove excess heat when you are working hard, so your feet stay at a comfortable temperature even during high-output climbs.

Ideal use cases

• High-altitude mountaineering
• Ice climbing and mixed routes
• Expedition camping in extreme cold
• Winter hiking and snowshoeing

Good to know

Machine wash warm and tumble dry low. Do not use bleach. These socks are made in the USA and come in a navy colour that pairs well with any technical boot. Available in EU sizes 43 to 47, so measure your foot length and compare with the brand size chart for the perfect fit. Whether you are on a two-day climb or a multi-week expedition, reliable socks like these are non-negotiable.