King Electronic Cam Angle Indicator

I have a King Electronic cam angle indicator. it has a cam dwell guage that reads 0 to 90 and says KING SYSTEM. has adjustment knob for cam lobe adjustment, pllarity sw which reads pos off neg, and a toggle switch that reads cam angle test adjust. it is a metal case with a wooden front where the dial and guage and switches are located. It has a tag on the side which reads KING trade mark reg. made in u.s.a. tester no. 275/ type CA2/ 6 volts/ BAIT/ cyc./ THE ELECTRIC HEAT CONTROL CO. CLEVELAND, OHIO.   if anybody knows the date in which this was made and or an approximate value please let me know you may post a comment and or email me at [email protected] thanks

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