This is a shell jacket which means you will have a shirt on underneath it. In my opinion this is labeled at least one size larger than it actually is. I am very surprised at what others are saying about the size and fit. This is a slim fit cut meaning it fits skin tight to a thin bodied, flat stimached  and small busted woman and the arms are skintight all the way down,  it includes the longer sleeve with the hole cut out for your thumb.

 A shell jacket is usually worn as the first base layer, you are meant to wear on top of it:  a fleece for warmth or a rain jacket for protection against the rain. This is not a windbreaker either. It is just a shell layer.

I will rate it four stars because it is a nice jacket with useful features wearing to exercise or for other active outdoor use even though this jacket is so small I cannot zip it or use it as intended. Be very careful with your size selection   remember you're also going to have a shirt on underneath this that will add bulk under this shell.