Hi,
Bearings, 608 2-RS Bearings - 2RS is as I understand it, just like ZZ, but where ZZ has metal bands, the 2RS has rubber bands. Looking through the assembly, I can’t see why the components should be 2RS over, say ZZ.
Has this something to do with how well the screws fit ?
If there are no difference, it could be advisable to change the BoM list 
RS=Rubber shielded on top of the regular ZZ, meaning it keeps the dirt out better. Keeping the BOM.
Cool, didn’t know - but that means, besides keeping dirt out, there is not functional difference? The design as such doesn’t rely on 2rS ? (I mainly ask bc I already have a few dozen ZZs in stock, from a failed 3dprinter attempt…)
I used zz bearings in my first build. It works fine but I’m going to to use 2RS in the next one.