I wanted something a little fancier than a light colored puffer jacket for summer. This blazer style jacket is perfect. It is lined, and the material is kind of wool-like. Heavier than I expected, this will definitely keep me warm in the grocery store and offices with chilly air conditioning! I am 5'5\", around 135 lbs, and chose size small. It's a perfect fit with a t-shirt underneath, probably too snug to wear over a sweater. I live in SoCal, it will be great in the fall and winter, too.