Metal wheels on Kobra 3/Bambi A1 motion systems?

Hey all. I'm looking at videos of teardowns on the Kobra 3 and the Bambu Labs A1. Whilst the Bambu uses a linear rail on the X axis, it looks like it uses some kind of concave metal wheels on the Y axis and the Kobra 3 seems to use metal wheels on the X axis.

I can't find any info on technical details on the motion system on these two systems - are these printers using their own proprietary designs for their motion system or am I just missing something that I can't see on the teardown videos?

Asking as I'm really curious since most printers use either POM wheels on extrusions, rods or rails where as these look almost like rods with pulley wheels on them