Great Product at a great price.

These are 608RS bearings a good value. At first they were listed as having a nylon bearing cage but, in fact, they are steel. I contacted the seller (a small startup) and they responded immediately and corrected the description. Unlike another reviewer here, I did not find the bearings that I received to be "full of grease," though. There certainly was some grease inside. If using these for light loads, like skateboarding, try opening up one side and putting a couple of drops of light oil in (I used silicone oil) and give it a few turns to thin out the lubricant a little. That really makes these spin well. If using these for heavy loads and high RPM, leave the grease in, of course, without thinning. But, if using them for light loads, thinning the lubricant may just do the trick for you.

Used these and some 1" square aluminum tubing to build some truck bed drawers. Worked fantastic. Get some m8 bolts, washers, and lock nuts and you're good to go.

When I first got into 3D printing, I didn't know these things existed. I quickly found, however, that the 608 is the bearing of choice for many 3D-print projects that need rotating parts. I really don't know how long it is going to take me to use all of these (so far I've only used them in three projects), but I couldn't pass up the quantity price. They fit perfectly in every project that calls for a 608, they turn smoothly -- what's not to like.

WayneChicago wrote an excellent review. You should read that before reading mine. He outlines is perfect detail all the reasons why people buying these are complaining. Only he says it with tact and finesse. But I don't have that. So if you want a more direct rebuttal to the absolute nonsense you'll read in the product review section about these being akin to sand-filled garbage, then keep reading. However, If sciency words are just flowery nerdspeak to you and breaks your brain, then just sop reading now and go buy the grossly overpriced BONES bearings. They make the cool whizzing sound on first rip out of the box. Plus they're all shiny and you can't put a price on shiny, can you?

Now....If you're not a mental tree stump and words with more than 3 syllables don't frighten you, then by all means, continue on!

General Complaint: These are covered in some kind of oil and don't spin.
Rebuttal: That is CORRECT! The insides are packed with grease which is thick. Think cooled bacon grease. When you reheat cooled bacon grease, what happens to it? It thins out and becomes more viscous, right?? Same thing applies here. These are packed with grease because they're designed to be run in machines for long periods of time. Which means heat from rotational friction, which means the grease viscosity inside the bearing thins due to thermal conduction. This is WHY they were built the way they come in the box. So you can use them in machine type applications right out of the box, where thermal friction needs to be considered.

Ok, but can I still use them for skateboard or roller skate wheels though? YES, you can but you need to do a little work first. No big deal if you're not lazy. If you want these bearings to spin like a fidget spinner and go whizzzzzzz, you have to dissolve the grease inside the bearings and use a thinner lubricating agent in it's place. WayneChicago goes over how to do just that in his review. So I don't have to. Thanks, Wayne! *fistbump*

And if you can't find WayneChicago's review, don't act like you don't have Google. Just look up "How to dissolve grease in ball bearings". This isn't rocket science...

As far as I can tell, the outside grease feel is just machining oil which is often times applied to metal surfaces as a water repellant to keep the surfaces from rusting due to atmospheric conditions. Wood workers and machine shop operators know exactly what I'm talking about. Probably some mechanics too. Why would they do that? Well...where are these things made? Is there any water that might get into the bearings in transit from the factory to your house? Yeah, there is. There's literally an ocean of it. Highly corrosive salt water to boot. So, in order to make sure these don't arrive as little jammed up rust cakes at your doorstep courtesy of the Amazon delivery guy, they coat them in a light oil or maybe even some of the inner grease to prevent that from happening. You're WELCOME!!

It's a prophylactic measure against people who don't know better. And also so people don't buy these and end up in their review section complaining about that too. Like so many other people are out here doing. The people complaining simply don't know what they don't know. And are trashing a decent product for the price from a company that is CLEARLY putting in an honest effort to deliver value to the consumer for a VERY REASONABLE PRICE.

Some of these might have manufacturing defects, Some might last longer than others. When I bought mine they were under $0.30 each. I'm not putting mine under heavy load for long durations anyways, and I'll have PLENTY of replacements should some of them give out, as they sometimes do. I have not tested them yet but I don't need to to know that I DID NOT get screwed on the transaction. This is EXACTLY what I expected and I'm sure will exceed my expectations in performance. Sure, you get what you pay for. But if you know what you need to know before making a purchase, you'll find INCREDIBLE value in these bearings given you're buying them for the right application. If you find yourself with a chapped ass complaining about this product because you didn't know what you needed to know before making the purchase, chances are you also didn't take my advice and spring for the BONES.

And that's on you, playa...

-5 Stars.