Vintage Struthers Dunn Electronic Relay. Used/ Parts. Please Read..  I do not know the history of this unit, however after a career in electronics, I have not encountered an operation that utilized one of these.  This unit shows to be an AC unit as per the tag (please see the image). I dare say that it is probably best utilized as a collector's piece.  Looks clean and useable, but I cannot swear to it.  Sold as parts.. Ships via USPS.