The Mount Whitney Vest is your all-season, stay-warm solution. It turns any shell into an ultra-warm, go-anywhere combo. You control your comfort. NuDown's Variable Insulation Technology, a system of trapped air surrounding the torso, allows you to endlessly adjust your warmth in nature's constantly changing conditions. You'll be comfortable from sun-up to sun-down, without the hassle of ever stopping to add or drop a layer. Powerful Warmth: When you really need protection from the elements, NuDown jackets and vests offer impenetrable warmth. At max inflation the vest will snug firmly to your torso securely trapping your body heat. At the same time, this internal air pressure blocks the wind from compressing the material. Picture a down jacket in blistering winds: as the wind blows, it moves the surface of the jacket closer to the surface of your skin, thus losing the loft that had provided the warmth. NuDown jackets and vests are immune to compression at full inflation capacity. You'll never feel the cold metal of the chair lift again! Call NuDown at 775.455.4656 or visit www.nudown.com for support.