This image shows a speed selector switch on a record player (turntable). The numbers 45, 33, and 16 represent the RPM (revolutions per minute) settings, which control the playback speed of vinyl records.
•45 RPM is typically used for singles (7-inch records).
•33 RPM is used for LPs (12-inch records).
•16 RPM is less common but was sometimes used for spoken word recordings.
This meme is saying that if you recognize this, you might be “old as dirt,” as it refers to a technology popular before the digital music era.