A Pittsburgh man acquired the items from his great aunt, who was married to one of the attorneys whose law firm represented Edison in patent lawsuits.
Tags on five of the six keys list the doors that they opened, including the Menlo Park lab which Edison opened in 1876 that became known as the "invention factory".
It is where Edison was credited with perfecting the incandescent light for commercial purposes. He created two of the bulbs up for auction that were part of a collection used in patent infringement lawsuits.