A quick warning if you are expecting clean free spinning bearings these are not for you. These bearings come packed with some of the worst grease I've seen. I took the time to soak them in degreaser for 6hrs then treated them in boiling dawn water for 20 min. After rinsing and drying them and applying some quality oil they spin good enough for the filament spool rollers I purchased them for. I only had 3 bearings that were seized up due to internal damage so all in all it's a great bargain for what I wanted them for.

These are a good buy if you are looking for okay quality. I only had a handful that were so bad that they were not useable.

They do need some work to get them running smoothly. The grease that these are packed with is rather thick.

If you need a super smooth bearing this is not what you want. If you need okay, cheap bearings in large quantities then these are a great choice.

The media could not be loaded. I had gotten 100 of these for about $18 USD or $0.18 each. This is extremely cheap for a bearing and if you get even a okay bearing for that price it is hard to complain.

However in honesty the bearings I have used so far out of this are what I consider good. Not amazing or exceptional... But definitely good...

The product boxes (NOT the boxes they are shipped in) for the bearings have no markings at all on the manufacturer and mine are of poor quality falling apart just from moving around the bearings so they are no good for storing the bearings in long term.

The bearings come in sets of 10 in a tube in two boxes of 50. The Tubes are flimsy but convenient for long term storage and protection.

The bearings themselves are sticky, so much so they are stuck together a bit when first pulled out. That seems to be mainly a surface thing though as most rotate smoothly. (Some do need a bit of breaking in though.)

It could be a thick grease from the lubrication or something put on the surface to protect from corrosion.

These bearings are 608ZZ bearings meaning they have 8mm bearings inside an a piece of metal to protect them on both sides.

An important thing is there is a quality discrepancy across the 100 bearings you get. Some turn much easier than others, and some are quite stiff right from the beginning.

I have not had any straight Bad Bearings yet though, just some that are just okay. Which can still be used for some things. (Like not great for a skateboards but fine for a drawer roller.)

You'll likely want to sort through these bearings (grade them) and pick and choose which ones you want for your specific applications.

What I found though is that even the best of these bearing are still kinda stiff compared to really good bearings (Like couple buck each bearings.) But again at such a cheap price it is really hard to complain.

I have been using some these bearings over 6 months on my 3d printer for a filiment spool roller and it works amazingly. They spin smooth and without issue. (No more the spool jumps and shifting noise...)

I also am using two more on a filiment feeder to the printer which too has been working great.

All which I show in my pictures.

Additionally I just used two for a VAWT or Vertical Axis Wind Turbine. It is just for some small scale testing right now but as I show in my video. The bearings work great for that too.

I do personally suspect if these bearings were cleaned of the sticky grease or oil on then and relubbed with better quality stuff they will work better. But being ZZ (Covered) Bearings that is a bit more work then normal.

I have not tested yet but may in the future.

On a last note I am fairly confident these are reject bearings from a factory as I see a lot of small imperfections on them. Like Dents on their shields, the center bearing column being slightly different size (Lengths) or a little more play then normal.

That is likely the cheap price and quality mix. But as I said it before, the price makes it worthwhile to get for light duty stuff.

Also if you were looking to make a turbine or wind ornament like I have, the perfect size rod that fits in the bearing hole is 5/16.

Hope this was useful.

I bought two other 30 packs for more money. These are just as good. My main use was for 3d printing spool rollers. They work as is perfectly for that purpose. OK I do wipe off the outside grease.

I worried that I might need really low resistance for spool rollers. But in fact a little resistance helps. These are nearly perfect with the factory grease friction.

After having too many of these I 3d printed some fidget spinners. These also work well for that purpose. With the grease they don't spin well. If you just hand wash them in the sink with dish soap and water they spin very well. I pulled off the metal sides to clean them even more, but you only gain a little bit for the effort. Same with adding any oil, or Teflon. A drop does help quiet the spin.

I should have bought this first.

Using for 3d print projects. Once you pull the covers and clean the gunk out, relube them and recover them they work fine. Great deal for 100 of em