Rocky Men&rsquo;s Wicking Thermal Underwear 2 Piece Pants & Shirt, Long Johns/Sleeve FIT & COMFORT: Order one size up for best fit. 65% Cotton and 35% Polyester fabric blend ensures superior comfort and lasting shape and size. STAY WARM & COZY: This thermal underwear is made of a waffle knit with cuffed sleeves and pant legs to retain body heat and keep you warm. PROTECTION FROM THE ELEMENTS: This moisture wicking prevents perspiration from accumulating on the skin and protects from strong winds. MULTIPURPOSE: This thermal underwear set is great as pajamas or as a base layer under athletic wear, work attire, or casual clothes in cold weather. MADE TO LAST: Rocky thermal underwear is midweight with good quality stitching and shrinkage controlled for long-lasting wear even after washing.