evo.com | Burton Long Underwear Bottoms > Real mountain warriors know the key to staying warm on the hill starts with the layer that's closest to the skin. With a super warm base layer like the Burton Heavyweight X Base Layer Pants, you can be toasty warm in your shell, even on the colder days of winter. Four-way Stretch Fabric This product may contain chemicals known to the State of California to cause cancer, or birth defects, or other reproductive harm. Next-to-Skin Fit Hugs the body with minimal extra fabric. Heavyweight 300 Living Lining Cold mornings to sunny afternoons, fast turns to slow chairlifts-a day on the hill is filled with extremes. Burton's Living Lining offers automatic climate control without added bulk or weight, so the one thing you can count on is consistent comfort. When you're warm, breathable pores on the Living Lining expand to release excess warmth and prevent overheating. When you're cold, breathable pores on the Living Lining shrink to trap body heat and keep you warmer for longer. Provides consistent temperature regulation without adding bulk or weight. Quick Drying and Highly Breathable | Women's Burton Heavyweight X Base Layer Pants 2026 - X-Small Black