Gisafai300 Pcs 608-2RS Skateboard Bearings Ball Bearing Double Sealed Miniature Deep Groove Roller Bearings for Skateboards, Inline Skate, Roller Skates (8 x 22 x 7mm)

I do 3d printing and these bearing have suited me for several projects so far.

These bearings are as described and function okay. They are fine for what they are, the cages are plastic, and the inner hole is roughly finished on many of them. My chief complaint with these, and other cheap bearings I've gotten is the schmoo that coats them. They all seem to come with a sticky protective coating which makes them unpleasant to handle and require cleaning or breaking in to get them to roll well. Given the seals, getting the schmoo out of the races is a pain. That said, these are destined for utility applications for me, heavy drawer slides, spool rollers, etc. and they are just fine for that. For tooling or skateboards and the like, I'd choose something more refined.