The Biltin bearings were the first in the industry to use the integrated race system. They are regarded as one of the most durable and can put up with a lot of punishment. By using an integrated spacer bearing you can tighten your bearings all the way without them slowing down, making for smoother slides and more durability. Sometimes you will need to lube them because the seals are not super tight, but this loose seal means no contact for a faster bearing.
Specs:
Bearings with a intergrated washer and spacer (10mm) for perfect allignment.
Available as ABEC 7.
Per tube of 8 bearings