[ Maybe Mabel was right. Maybe calling this a date wasn't actually wrong at all. ]

The 7xxx series is even stronger, especially 7068, but getting a sample of that . . . it's a little bit harder, here. It's a zinc alloy instead of copper, but just like with 2219 . . . it's really the hardening process that makes the difference.

You've done a lot of metalwork, haven't you?