This is an irregular long-sleeved thermal shirt from the US military. I purchased it as deadstock in a bag from a used clothing store, but I'm selling it because I haven't had a chance to wear it. The reason for the irregularity is that it has a twist overall, and the sleeves are attached slightly differently on the left and right sides. It might be noticeable if you wear it in a just-right size. Size: MEDIUM 38-40 (as indicated on the tag) Although it's unused, it's been in someone's hands once. Please refrain from purchasing if you are sensitive to such things.