Columbia Sportswear Men's Omni-Heat&reg; Base Layer Top - Midweight, medium Sage 85% Polyester 15% Spandex Omni-Heat thermal reflective system reflects and retains body heat for an average of 20% more warmth Omni-Wick advanced evaporation technology moves and disperses sweat away from the body for rapid evaporation Ergonomic flatlock seams Long sleeves Midweight base layer