Heading into the backcountry late in the season calls for the heavyweight warmth of the Core Merino 330 Zip-Off Bottom. Our heaviest-weight merino wool blend keeps you warm on the coldest hunts of the year and regulates temperature to maintain comfort when you're on the move. Merino wool is also naturally odor-resistant to minimize smell on extended trips, and our ArmorSpun merino wool is reinforced for superior durability. We then added a recycled synthetic lining quickly moves sweat away from your skin to keep you dry and warm. And when you need to shed a layer, side zips let you remove this bottom without taking your boots off, making this baselayer ideal for long expeditions and shifting weather conditions.