Spandex is added to the cotton fabric to make the undershirt more stretchy and adapt to every movement The extra-long back hem keeps your undershirt always in your pants Comfortable and breathable without tightness Label-less design, no more itching for all-day comfort V-Neck, invisible under shirts, sweatershirts etc. Model infos: Chest 47", Weight 240 lbs , wearing a size XL; Chest 40", Weight 176 lbs , wearing a size M; Chest 39", Weight 180 lbs , wearing a size M Stretch undershirt, made of cotton and spandex. More elastic than traditional cotton undershirts, while having better durability. Unrestricted and adaptable to a variety of activities