Intraknit Thermal Merino Base Layer Bottom – Men's

For cold-weather trail running and mountain days where your body temperature swings hard, this is our go-to merino base layer bottom. Body-mapped Intraknit construction places insulation and ventilation exactly where you need them, so you stay warm without overheating. Flatlock seams and a merino blend mean you can wear it all day against skin without a single hot spot.

• Intraknit construction zones targeted insulation and ventilation to match how your body actually moves and generates heat — no uniform thickness, no unnecessary bulk
• Merino wool blend delivers natural warmth and softness with built-in odor resistance, so you stay fresh across long days and multi-day trips without synthetic funk
• Flatlock seams sit flush against skin to prevent chafing under base layers, hiking pants, or a fitted shell during sustained technical movement
• Elastic waistband holds its position under outerwear without rolling, bunching, or riding down during aggressive climbs or descents
• Charcoal Heather/Black colorway keeps a low profile under anything and doesn't show sweat — available in S through XXL for a full range of fits