Waiting out an alpine bivy will be a lot more nice in these warm, stretchy bottoms. Patagonia's warmest synthetic baselayer, the Boys's Capilene 4 Expedition Weight Bottoms is updated this season to provide even more effective insulation, improved breathability and faster dry times during high-output activities in cold conditions. A smooth jersey face glides beneath layers and the brushed fleece interior warms, wicks and feels wonderfully soft against the skin. With a brushed-elastic waistband for softness and a effective fly. Made with 5.9-oz Polartec Power Dry with Gladiodor odor control for the garment. Recyclable through the Common Threads Recycling Program.