MicroClimate Zoning construction for built-in warmth, breathability, and stretch?wear alone or under a shell. Polartec ThermalPro Monkey Phur body provides supersoft heat-trapping warmth without weight. Polartec Power Stretch panel promotes breathability. * Stretch hem and cuffs seal in warmth. Zip handwarmer pockets. Chest pocket for maps, snacks, and other goodies. * Semifitted: loose enough for layering and freedom of movement.