First time I've seen that question on a forum. Darned if I know, and I think they were made by a company named "Airchute" in Detroit area that has since gone out of business. But if nobody else comes up with the answer, you might try calling "Seat Belt City" in NJ at 908-719-2354 to see if they know. They claim to restore old Corvette seat belts, and to sell 58-71 Corvette seat belts.