They are sealed bearings, think Mopar "green" bearings. I had them in a few of my cars.

But as pointed out ceramics are not cheap for sure. And at least for us not sure you will saw anything on the slip, but it rolls so much easier has to be something. But never heard of or seen anyone do any real A-B-A testing to prove any real gains,be difficult for sure. Honesty most guys have enough drag everywhere else not sure they need to worry about them. I mean if you have a ceramic front wheel bearing and your front brakes drag whats the point. I can tell you in Comp and Pro Stock they are used a lot as well as some of the SS and Stock guys.