This isn't your ordinary mountaineering fleece. Sure, the slim fit makes it easy to layer under a waterproof shell and the stretchy double-weave fabric is ultra-warm and mobility-giving. But engineered with WindWall fabric, it shields from the effects of wind chill without making you feel hot or stuffy. We've even added lighter fabric pieces to the underarms for additional breathability when hiking up mountain paths or navigating steep climbs. There are plenty of pockets, of course, and on top of that, it's made from recycled materials, leaving a smaller footprint on the places we explore.