Go Athletic mens thermal underwear is a heavy weight thermal coldgear is made of a high-quality polyester/spandex fabric that wicks away moisture to keep you dry with no sticky or clammy feeling, while providing you a base layer of warmth that you can wear comfortably Our mock neck long sleeve thermal shirts are the perfect base layer shirt to wear under your uniform, workout gear or everyday clothes while doing any type of cold weather activities. The fleece lining will keep you warm and the stretchy fabric will not constrict your movements or restrict your range of motion. Its almost like a second skin! Stay warm and dry during winter activities, buy a GO ATHLETIC men's long sleeve thermal shirt with mock neck today! SMALL : fits 34-36 Chest, Length 27 , Sleeve 24.5 MEDIUM : fits , Length 28.5, Sleeve 25 LARGE - fits 42-44 Chest, Length 29.5, Sleeve 26 XL : fits 46-48 Chest, Length 32, Sleeve 26.5 XXL : fits 50-52 Chest, Length 32, Sleeve 26.5 3X: fits 54-56 Chest, Length 34.5, Sleeve 26.5