I ordered the size M. That is my usual size and they fit great (I am 37-29-37). They are unfortunately very thin. I saw other reviews and was very hopeful, but out of the package you could see they were a little lighter blue than pictured. They get lighter once on, but a bigger size and they wouldn't stay up. Just holding them in the air, they are see through though. I actually expected that, so that was only 1 star to me. But the bummer is they are VERY easily snagged. I have barely worn them a work day at this point, and they have 3 snags from my wedding ring (I am assuming). I hardly ever snag pantyhose so this was very unexpected.