+ The waffle fleece material really holds warmth well and lets moisture through. Put thermal underwear, a 300g/m2 fleece sweatshirt, a field uniform, and good boots over this and you can easily walk around the forest for a dozen hours at a perceived temperature just below 0°C (I checked). - However, this underwear is really badly sewn. I bought XL. It's a bit too loose, but the length is good. I look more like I'm wearing a tight tracksuit than underwear. Very low rise at the crotch. Despite that, the pants are tight at the buttocks, so when sitting down the underwear rides down. The leg length is just enough to barely go into the socks and they can slip out. Putting the sleeves over your thumbs causes the material to dig into the skin, so after a few minutes you have to remove them because you can't stand it. The collar is OK; it fits snugly around the neck but isn't choking. Since this underwear is half the price of models from other brands, you can buy it if necessary.
