The logo mark on the back collar clearly shows the size as M, but the text on the product label on the left side is unreadable, so it's unclear, but I think it might be a brand from a sporting goods store. I only wear it when watching sports, putting a short-sleeved uniform of the club I support over it. I don't wear it when I play sports myself. #sports #sportswatching #undershirt #highneck #black