The base of this vintage 1 quart Pyrex measuring cup is stamped FOR GENERAL HOUSEHOLD AND PHOTOGRAPHIC USE ONLY TRADEMARK / PYREX / ® / MADE IN U.S.A. / N-12. It was manufactured in the 1950's. It is well used, with blemishes and with much of the red lettering now white. The inside of the rim shows the most wear, likely from other measuring cups nesting in it. See all pictures. Questions welcome. From a smoke free home. More Pyrex in closet!