2 pieces: 1 Men's Thermal Shirt, 1 Men's Thermal Pant 100% Cotton. Size(s) S, M, L, XL and XXL These heavyweight cotton men's thermal sets are engineered with advanced performance and endurance in mind. The cotton-blend fabrics help you endure the harshest environments. Advanced thermoregulation technology works to keep you comfortable in a variety of environments.Featuring premium RetentionX waffle-knit fabric, these men's thermals feature a blend of cotton and stretch yarns. Multi-Wick technology keeps you warm and dry.Breathable waffle-knit thermal construction keeps you odor free. Functional fly.