Excellent shirts, good weight and they hold up well and retain their shape even  under heavy activity and repeated washings. I have ordered several in the past and all have held up very well compared to other thermal shirts I have bought from far more expensive brands over the last 50 odd years.. These may be the best on the market and they fit perfectly, neither too tight nor the least bit baggy and the elastic at the sleeves doesn't stretch out nor do the collars sag with time.  You can't find better on the market for the price.  I  used to avoid dacron blend fabrics because dacron usually ruins the insulation quality-- they're either cold in winter or hot in summer , just the opposite of what you need and  it usually shortens the life of thermals in the wash since the dacron cuts the cotton content as a rule and it ends up over time washing out leaving a thin dacron version of your n=once nice thermal. B Not so with this brand. I don't know what they do differently these days, but these are excellent shirts. The issue with 100% cotton is that they shrink or stretch out disproportionately and end up stretched out after a few seasons besides costing a lot more for any sort of decent weight. The other issue with most  name brand thermals especially all cotton ones by other makers-- even expensive ones-- eventually stretch widthwise at the expense of length and leave your belly and back exposed to cold. Not the case with these Southpole shirts I have some of these Southpole shirts that are several seasons old and still fit like new.