Those look like stuff that B&S/M-W has used in the past.
Minibal makes some links which are the same size but (width-wise) less bulky.
To answer your specific question...
If you want links and screws that look just about like those in the picture - and want to buy them from Allied Supply Corporation, you would probably order (or have someone order in your behalf) MW100 (link) and MW101 (screw).
I just checked their pricing, and it's "interesting"...
That having been said, since about 2 & 3/4ths years ago, the pricing of just about everything has become "interesting".
An economical alternative would be to (until you get some more "reasonably"-priced metal links - if your heart is set on metal) get two of these:
https://www.dubro.com/products/e-z-adjust-ball-links
They are drilled for S.A.E. 4-40 threads.
Metric (metal) links are going to be drilled for M3 x .5 threads (.118") so you probably (??) won't be able to muscle 3mm screws (planning for replacing them later) into the plastic DuBro links...
...but (if you have an aluminum hand vise) you can drill out the DuBro stuff to 3mm (and use 3mm screws)...OR (later) you can just use the .112" o.d. DuBro 4-40 screws, which will work FINE with European metal links. (Just tighten the screws and there will be no rattle).
note: I put Dubro links (decades ago) on my treasured F tuba. They are quieter than any metal links (which eventually wear and click), and the DuBro plastic are adjustable tension. They're not "cool" but (in my view) they're actually BETTER. btw...I've not swapped out ANY of the originally-installed DuBro links...They have ALL lasted (and I've played that instrument a TREMENDOUS amount).
Here are some thirteen-buckers (3mm thread) from McMaster/Carr, but I view them as being too friggin' LARGE...
https://www.mcmaster.com/59935K13/