The Microdown Vest was made for the ounce counters who need rapid heat when the weather turns south. It's hyper-light, built with water-resistant ExpeDRY goose down, and occupies zero pack space. What makes the insulation across our Microdown system so unique is that it stays dry and warm, even in relentlessly damp conditions.Perfect at altitude and again around camp, this lightweight 700-fill down layer is destined to become an essential piece of your core-temp management program. You'll feel its weightless warmth, on demand.