First impression
The shirt is made from slightly thicker material and is very stretchy and close-fitting, almost like a compression shirt. You'll also notice the areas that are made from a slightly bulkier material with a large surface area (such as the back), which helps to wick away moisture particularly well.
Tester & test conditions
I am 183cm tall and weigh just under 80kg. I tested the shirt in size L, which fits me well, but it shouldn't be any bigger. Due to the pronounced stretch properties, I think size M would also fit me well.
I have used it in the ski area for freeriding and piste skiing as well as on numerous ski tours.