The Hot Chillys Pepper Bi-Ply Crewneck uses a two layer knit that traps air between the layers to keep in body heat in and disperse moisture away from the skin. We used our special "chilly seasonings for added moisture management and lightly sanded the polyester yarns for added warmth and comfort. Features: Flat seam construction to reduce bulk and skin abrasion Crew neckline with binding at trim Drop tail for easy layering