Question: how old are 45 records?
Answer: Also released in June 1948 were three series of 10-inch "LPs" and a 7-inch "ZLP". RCA Victor developed the 45 rpm format and marketed it in March 1949. The 45s released by RCA in March 1949 were in seven different colors of vinyl depending on the type of music recorded: blues, country, popular, etc.