NuDown Men's Mount Whitney Vest 100% Nylon Made in the USA and Imported Adjustable warmth, via NuDown's proprietary Variable Insulation Technology, empowers you to be precisely as warm as you want Add air to add warmth or release air to cool utilizing the pocket hand pump and release valve, also creating a supportive, athletic fit 100% mechanical stretch nylon waterproof shell, Polartec WindPro windproof breathable sides, Primaloft Gold insulation collar Stays warm when wet, indefinitely loft retaining, eco-friendly alternative to down feathers Welded seams, double-slider waterproof YKK zippers w garages, limited lifetime warranty, internal stash pocket, adjustable draw cords