Gary, It's magnetic and I think it was manufactured by King-Seeley. Here's a website which somewhat explains the workings: http://www.innerauto.com/Automotive_Systems/Drive_Train/Speedometer~odometer/ Regards, Joe Fulton Salinas, CA _______________________________________________ AMC-List mailing list AMC-List@xxxxxxxxxxxx http://www.amc-list.com/mailman/listinfo/amc-list or go to http://www.amc-list.com