This is for use with a digital voltmeter that I install on many of my RC rigs. Here are the voltmeters I use: 12v Digital Voltmeter: https://www.amazon.com/gp/product/B00YALV0NG/ref=as_li_qf_asin_il_tl?ie=UTF8&tag=harleydesigns-20&creative=9325&linkCode=as2&creativeASIN=B00YALV0NG&linkId=b846b52425c9698561c278a01219440a

You can find my installation of it in the following video: https://youtu.be/ufrRhUNSXiY