Mens Thaw Pure Silk Thermal Underwear Long Johns In the winter weather a base layer under your winter clothing is essential! 100% Silk Silk means warmth without weight or bulk, its insulating properties retain body heat more effectively than any other natural fabric. Silk can soak up to 30% of its own weight in moisture and still feel dry as it gets locked away inside its structure. This enables the 'wicking' process that takes perspiration from the bodys surface into the next clothing layer, effectively keeping the adventurous sportsperson warm & dry Thermasilk underwear can be washed time & time again, as silk has a strong natural composure & will ensure maximum comfort in the harshest weather.Stay warm and cozy with the Hanes Men's Thermal Pants. Do away with cumbersome layers of warm clothing with this waffle thermal pant. If you are working in a place where it isn't safe to wear clothing that could restrict your movements, these men's thermal underwear will be perfect for you. Hanes thermal pant is made from soft waffle knit fabric that is lightweight and breathable. It stretches to give you the right fit. These thermal pants are available in a range of sizes from small (30-32 inches waist) to extra large (42-44 inches waist).