Wool fabrics have built-in climate control. Wool is a natural insulator and keeps the body warm in winter and is naturally breathable to keep the body cool in summer. Wool garments are excellent for winter clothing. The scales on the surface of the fiber and the crimp in the fiber create little pockets of air that serve as insulation barriers and give the garment greater warmth. Lightweight wool of sheer construction can be comfortable for summer wear in suitable garment styling because of its thermostatic quality.