The first version label said:
The Classrom Gyroscope
Developed by M.I.T.
Produced by AC Spark Plug
The Electronics Division of
General Motors Corp.
these may be AC Sparkplug part numbers:
58-9546A - MITAC the Classroom Gyroscope developed by M.I.T. produced by AC Spark Plug photo is for brochure. (10/30/1958)
58-9546B - Mitac for brochure. (10/30/1958)
58-9546C - Mitac for brochure. (10/30/1958)
This label says:
Cat. No. 74730 Serial No. --blank---
Volts: 115 AC 50- 60 ~
Central Scientific Division of
Cento Instruments Corporation
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