So I bought this compression stockings in size 39/42, although I otherwise the shoe size was 45. The delivery took place within 2 or 3 business days, which contrary to some reviews but was very quickly. The fitting stockings confirmed the above tip, because the small size (39/42 instead of 45) fit me very well. Now for the practical test: During the flight (round trip) I wore the stockings. During the entire time the compression was clear but very pleasant. Other than my companions, I had at the end of the journey no fatigue or feeling generally unwell in the calves. The sock looks visually good (unlike the "standard hospital compression stocking") and actually does not stand out. The second pair supplied is ideal for changing during the trip route.
Conclusion: I'm going to wear the stockings on other flights, because I have benefited significantly from the immediate effects of compression and unlike fellow had no calf problems. The second pair is very useful to change. Visually I see with this product advantage over other "standard" compression stockings. Unfortunately, I can say (blood clots of the leg veins) nothing objective on the effectiveness of stockings in relation to the prevention of venous thrombosis because I lack the direct comparison to "hospital socks" a certain level of compression. I think the compression effect of the stockings in my case (no other risk factors for thrombosis) for absolutely sufficient and will therefore stay with this product.