This is a PYREX soup mug used by United Airlines in the late 1970s. Two types were used: ceramic mugs made by STERLING and PYREX milk glass mugs made by CORNING. The latter seems to be much more popular in the used market. This red-lettered mug was obtained as an unused item. Indeed, there is almost no sign of use, and there are no chips, flea bites, cutlery marks, or noticeable missing letters. There is a tiny hairline of a few millimeters near the bottom, which appears to have been made during manufacturing (see the red circle in image 4), but overall, I think it's a beautiful item that is not often seen in this condition. Size: Diameter 82mm, Height 56mm Please consider that this is a vintage item from about half a century ago before making a purchase.