The sweater fits like a glove, but you also have a very slim figure for a S size. The neck, I find a little tight because would calm can be a bit more space. The sleeves are very tight, almost stifling. There is the star trigger, because even at my slender son they constrict his movements. Why the sleeves are so closely, remains a mystery, comfortable is different.
The sweater is very light and not intended for the winter, but ideal for cooler summer evenings. He is well-sewn, the quality is nothing to complain. How well he behaves in use, will then show yet.