Hmmm… I think it is possible that this is somewhat misleading information. "4-40" is the imperial thread size that has been originally designed and used on all Steinberger tuners. That's where the "1:40" tuner ratio comes from (40 turns to move 1 inch). They switched to metric with the later tuners, all guitar bridges have an M3 thread. On my bass jaws (4-string) the thread is M3.5. The length is about 40 mm.
So I'm not sure what BGS actually says here…
Bernd
5 wide is a later bridge, and BGS posted that for the "wide" jaws only - please see the list of instruments in my post above. That 4mm/40 size is NOT applicable to any other instruments, including the original Newburgh or any 4-string Steinbergers. So there shouln't be any discrepancy here.
That's why they sell the "original jaw" replacements WITH the rods included, while selling the "wide 5" replacement jaws without the rods
The jaws themselves are shaped differently. Here's the shape of a "wide 5" jaw:
And this is the "vintage" jaw shape:
:
