Our guides are wearing the Marmot Isotherm Hoody as their main piece of outerwear this winter. We couldn’t be more pleased! The Marmot Isotherm Hoody is filled with Polartec Alpha Pro insulation and topped with a Pertex Shell, making for a stormproof jacket that is warm, lightweight, and incredibly breathable. We have found this piece to be absolutely perfect for high output, cold weather activities like backcountry skiing and ice climbing. In the video below, Matt Wade reviews the Marmot Isotherm Hoody.