i bought this for my husband.  it's been the coldest winter we can remember and we're getting old, apparently.  he wanted long underwear, but i didn't want to buy him the cotton stuff because it wicks moisture and will make you colder if you happen to sweat.  did my research and found this product.  it's lightweight and makes a great base layer. keeps him warm but isn't bulky and also doesn't pull the heat out of your body if you happen to get wet.  sizing was right on, too.