For dark oclock starts in the mountains, you need technical insulation that keeps your skin dry when youre pushing the pace and your core warm when the action slows down. The micro grid fleece interior of Patagonia's Capilene Thermal Weight provides the greatest warmth combined with the greatest breathability of any baselayer in our lineup. Soft, stretchy and compressible, the Polartec Power Grid fabric has a smooth face that glides beneath layers and a brushed fleece interior to warm your core, wick moisture and feel smooth against your skin. Capilene Thermal Weight is bluesign approved, has 30 100% recycled content and is treated with Polygiene permanent odor control. Features include a flat waistband with brushed inner elastic for next to skin softness, a gusseted crotch for mobility and flatlock seams to minimize chafing.