I was so excited when I found this clothing line, "sizes run small" I am 5'7" with 30" waist  and about 130 lb and the US small is truly a US small meaning that I am swimming in the sweater. There is nothing slim about it although I might consider the shoulders and arms okay for a comfortable evening. I was really hoping that I found something that fits the slim guy, but no luck at all. Don't wast your money if you have a slim build and want to have a fitted sweater.