It was a little sketchy to order a one size fits all, but I usually wear a s/m, I'm a pretty basic body, 5'7 and 130lbs with a pretty basic build. It took 16 days to come which was a long time but it says 15-30 days so it was expected. It smells really weird when it comes but I just threw it in the wash. There also aren't any tags on it. But I actually really like it. it's a little short on my wrists but I just pull it through out they day or push them up. It's a soft material and it seems pretty well made. If you like it, buy it, if you don't wear a small or small/medium, don't buy it because it won't fit.
The sweater is definitely a small/ medium fit. I love the way it looks though! Probably my favorite sweater right now plus I get a lot of compliments on it. The sleeves are shortish but it's still really warm and comfy.