What is it? It's metallic and about 1-3/8" long by 3/8" wide by less than 1/16" thick. In the close-up pic [id=115852250] you can see that there are tapered notches on each side toward one end. This insulator, along with a handful of other McL 42's containing finishing nails, tacks and glazier's points were recently found on a section of line in Arizona. We know McLaughlin used cullet in his insulator production and quite possibly incorporated used window glass, accounting for the glazier's points, etc. Is this metal object possibly related to window installation? Any hardware gurus out there have a clue?
ANSWER: Thanks to Gene Hawkins, Richard McLaughlin & Bill Rohde for your replies. Dave Elliott seems to have solved the identity of this mystery item. This appears to be a piece of the attachment end of the flat spring material that inserts into a slot at the terminating end of a retractable tape measure. I've seen measuring tapes break at this point if they are overextended or just wear out from extensive use. Some of the modern retractable tapes are attached in a different configuration, but the earlier ones look identical to this. Mystery solved!