Title says it all. This upgrade is for the K8400 LM10UU bearings. The design is based on the stock on, altered for stability and greater diameter, not a ripoff of this Printing like paradise - Vertex 3D Printer - Whadda forum - Community Help and Support
No more oil, no more brass dirt, less noise (or not, depends)
It looks nice!
I see that you don’t have the tabs near the magnetic spheres that are on the original. Do you have any problems with the spheres dislodging during fast motion?
Thx! To be really honest, no, I never had that issue and was wondering why the tabs all this time 
I left the tabs off of my first attempt to redesign the carriages (for easier printing) and found out why they were there. Keep an eye on those spheres…
Now that you say it, sure, will take a look at it. My printer just finished an 18 hours print, they stayed so far