The only identification on the bottom is the letter.
Vintage Pyrex Measuring Cup 2 Cup Clear 516 Red Lettering USA D Handle
(6-Pack Value Set) Brand New Pyrex 1-Cup Glass Measuring Cup
Pyrex 1 Cup 8oz 250ml Glass Measuring Cup Red Lettering 508 Corning USA
1980s PYREX 1 Cup 8 Oz. 250 ML Glass Measuring Cup Mixing Bowl Red Letter USA
Vintage Pyrex 1 1/2 Qt. Divided Casserole with Lid in the Gold Acorn Pattern
Vintage Pyrex 1.5 Qt Oval Divided Casserole Pan Gold Medallion USA Ovenware
