This is a replacement capacitor plate for the AC Voltmeter Heathkit.If you are missing the capacitor plate inside the AC Voltmeter Heathkit, then you can use this file to have a plate laser cut or cnc'ed!For ours, we laser cut a melamine plate, and attached one of the outer capacitor lugs to the case for grounding it properly.In order to ensure we had the correct laser settings to cut through the melamine, we did a few test rectangles first.A better idea would be to use actual metal for the plate, as that is what would be included in the kit.For more information on this Heathkit please see: http://www.evilmadscientist.com/go/heathkit-part1