ColdPruf Men's Enthusiast Single Layer Long Sleeve Crew Neck Base Layer Top 100% Polypropylene Lightweight single layer engineering with an exceptionally soft feel Drop tail maintains coverage in various activities Seemless sides for additional layering comfort Tagless labeling and self fabric cuffs for extra comfort Moisture management system wicks perspiration and dries quickly Best used an a base layer for low bulk layering in cold to very cold weather and medium to high activity levels