I bought these to wear over tanks to the gym or under my short sleeve physical therapy work jerseys to stay warm during winter/early spring cool mornings. I am a small in women's shirts but ordered x-small in unisex, and they are great! Very soft, not shrinking, good length for layering, want but not too hot. I would never have known about Jiffy, but I saw a woman on vacation wearing one and liked the cut, and she told me her husband ordered them, and then she liked them so much she got her own. You will be happy with your VERY reasonably priced purchase!