I ordered the small, which was a S/M but works just fine. I am tall and lanky (5'8, 125 lbs, long arms) and it fits perfectly. The material is very nice and soft. Not sheer, not thick, just a thin-ish lightly ribbed material.

I can't wait to order this in every color, which I am about to do now. My arms get so cold at restaurants and this will fit nicely in my purse when we go out!!