This is a short-sleeved work shirt from A Bathing Ape. The size is M. It has been worn very few times, and I barely remember wearing it. This shirt was worn by a woman who usually wears L to LL sizes. Since the Isetan pattern shirt in size M fit perfectly, I bought this one in M at the store as well. When I tried it on at home, it was too big, and I couldn't wear it well, so it ended up in the closet. It's short-sleeved, but the fabric is thick.