Mountain Hardwear is adding the "Butter" fabric to their Men's line this fall. This super soft fabric has been extremely popular in the women's line. The "Butter" fabric consists of 89% Polyester and 11% Elastine. The Elastine allows the shirt to stretch and move with you. The Butter Man can be worn alone or as a baselayer. It's hard to describe the softness of this shirt. I notice every time I wear this shirt, my wife gives me a lot more hugs and she tells me how cozy the shirt feels.