DESC: Looking for warm winter boots? The North Face Men's McMurdo Winter Boots use 400g PrimaLoft insulation to achieve a -40F (-40C) temperature rating. Yeah, you could call them warm. Their Dri-Lex fleece lining keeps feet happy while the faux-fur collar adds a touch of style for around-town wear. The McMurdo Winter Boots also include TNF Winter Grip outsoles to keep you upright on slippery sidewalks and frozen trails.