Dual calibration strobe disk

These items were often supplied with the purchase of a turntable of the brand, Dual in this case. This one measures 4" in diameter and is only good for 60 hz electrical outlets. Generally, a fluorescent was used to make the strobe be seen better. Later adjustable turntables (with pitches) have a neon light that lights on a strobe design engraved in cast aluminium platters

-Year(s):1970s
-Retail: N/A
-Use: Strobe calibration for turntable speeds of 33 1/3, 45, 78 RPM
-Extra informations: Item made of thin cardboard.
-Status: In hand