Set of 4 Vintage RCA Logo Advertising Promo Tumblers.  Approximately 4 3/4 inches tall, 2 1/2 inches in diameter at rim, holding 8 ounces.  Red RCA logo on clear glass.  (Glasses here photographed with a paper insert to show the logo.)  Glasses marked with the Libbey Glass fancy L.  Probably dating to the 1950s, 1960s, as this logo was in use from about 1930 to the mid 1960s.  Vintage items in good condition, no chips, no cracks, light use.