I am 1.74 meters tall and wear the shirt in size S, as it should be as close as possible against the body. One characteristic of Techfit products is the (light) compression that reduces muscle vibration, thus delaying fatigue should. And yes, it really works.
Despite the narrowness of the stand-up collar is quite comfortable to wear. He does not take the air you breathe, and he covered his neck slightly, so not too much cold air comes in mind. However, I complete the neck protection through a scarf.
Otherwise, the shirt met each subsequent claim to functional underwear. It wicks moisture and keeps you warm. Of course it is not enough in freezing temperatures, but at around 5 to 10 degrees in combination with a thin running jacket I feel the temperature regulation as very pleasant.
My conclusion is, it may not always be the most expensive shirt. Because there is hardly anything that I miss to functions in this shirt.