For reference, my build is around 174.64cm. I usually wear RLX in size S or sometimes XS depending on the item. I wanted this design, so I went with a boys' size. The arms fit perfectly, like an XS, but I felt it had the room of an S in the body. Measurements when laid flat are: armpit to armpit 48.5cm, length from collar to hem is 64cm in the front / 68cm in the back. There's a slight fraying on the left underarm area, as if it caught on a golf cart? Please be aware of this.