Came in with some old radios…. Some sort of charge discharge gauge…. Has a jumper in back so must be for high current? Untested as found, not sure how to test. Looks like serial number is 65403. I assume auto related. If you know more please let me know. Please see all pictures and use zoom feature. Often the pictures describe the item better than words. I try my very best and list a lot of pictures, but are not posted as a “try it and see if it fits and send back ” type item. Please know if this is the item that works for you before you order. Thank You for your understanding on this. 36,000 + happy customers! Also please see the 12,200 + vintage radio related parts and other great antiques and oddities from old radio guys estates. Old Radio’s are Fun and parts are getting harder to find! Just like radio parts? Thank you for you order and please follow my store! New items added daily. Also you can go into my store and pick the category for easy shopping. Best to you and Many Thanks, Mike.