Odd conductors?

Ran across this yesterday; ‘wires’ of a type I have not seen before.

These were in a main panel, feeding a 100A main disconnect.

What are they called, please?

SEC flat zoomed.jpg

SEC flat.jpg

Looks like the factory bus bars coming out of the meter socket. They replace wire conductors.

Yes, Jim, they are definitely coming through a panel partition from the meter side…