I have some wool hoody's from icebreaker that are just like this - a lightweight hoody that you can layer over top of a t-shirt. Was looking for something lighter weight in humid summers (live in mountain southeast) and these are perfect. Very impressed with the synthetic material - wicks incredibly well. Bought a second one and some t-shirts as well. I am 5'6" with an athletic build (broad shoulders, narrow hips); 125#. I got smalls in the t-shirts and a medium in this because I layer with it. The small in this (I tried it) was too snug in arms/shoulders for me to layer. Great versatile everyday piece.