The Altitude Merino Base Layer is a lightweight performance layer engineered to regulate temperature, manage moisture, and maintain comfort during high-output outdoor movement. Constructed from a merino wool blend with articulated stretch zones, it provides warmth without overheating while remaining breathable during climbs, hikes, and alpine approaches. Designed to function as the foundation of a layering system, it performs equally well in cold mornings, windy ridgelines, and multi-day treks.