This is a polo collar shirt, or Oxford button-down shirt, made in the USA by Brooks Brothers. The size is 15½-1. Based on the tag, I believe it's from around the 1980s. It's a valuable vintage item. It has an American-style striped pattern. The fabric is neither thick nor thin, making it a great shirt to wear on its own. The collar and sleeves are in very clean condition, with no damage, stains, or discoloration.