The size is XS, but it fit me perfectly, and I usually wear a size M. It's a USA size, so it's a relaxed fit. It's 100% cotton. I removed the tag, but it's new. I thought it looked good when I tried it on, but the frills around the collar didn't suit me. I've added the measurements for each size. See the photos: ⑤ is the width under the armpits, ⑦ is the length, and ⑧ is the shoulder width.