Made from recycled polyester and bamboo fibers. Bamboo is naturally antimicrobial and hypoallergenic. It is a highly renewable resource which does not require fertilizers or pesticides to grow, or the use of chlorine in the bleaching process. This combination creates a soft, lightweight garment that feels like cotton and it naturally removes moisture and odor from your skin. Absorbs and evaporates perspiration effectively and efficiently, keeping you warm in the winter and cool in the summer. 69% bamboo/31% recycled polyester.