ColdPruf Men's Extreme Performance Dual Layer Long Sleeve Mock Zip Top 96% Cpt Performance Polyester, 4% Spandex Imported Two-layer engineering traps body heat between layers, resulting in chill-blocking warmth 1/4 zip mock turtleneck with drop tail maintains coverage during various activities Tagless labeling and flat seems provide a smooth fit and extra comfort Moisture management wicks perspiration and dries quickly Featuring ColdPruf Technical Fiber formulated with Silvadur Intelligent Freshness to minimize odor and odor causing bacteria on fabric Best used as a base layer or mid layer in very cold to extreme cold weathers or as outerwear in cool situations