CARHARTT. MBL112SHADOW. MENS BASE FORCE HEAVYWEIGHT BOTTOM. SHADOW GRAY. A comfortable essential done the Carhartt way. These men s heavyweight thermal bottoms are made of the perfect blend of waffle knit polyester and spandex for easy-wearing warmth that wicks sweat and fights odor. These tights give you the range of motion and warmth you need when battling the seemingly unbearable cold weather days.