Button up Eddie Bauer shirt, 3/4 sleeved. Both the primary material and side panel material are stretchy. It is a size XL, but I am a size large and it fits me. So, it might be an option for some people who are also size large. That is a subjective comment based on my personal experience. There is a very small hole in the back collar seam (see picture). Measurements are in the pictures. Non-smoking, dog friendly home. If you have any questions please put them in the comments.