I didn’t realize that, @Mike_NL . . . but why would Fender sell a set of “American Series” locking strap buttons that don’t fit the strap locks supplied with their “American” Ultra Jazz Bass?
I examined those buttons and they looked identical to the ones on the Ultra.
I did find a difference between the Ultra locks and the Schaller locks, though. The Fender locks have a plastic tooth instead of a metal one. So I’m going to order a set of Schallers and compare them.
Thanks for your response!
Cheers
Joe