Since I found a pair of 7209 Fafnir Abec 7 bearing amongs some of the
stuff I took home recently, I did a little research. Looks like ABEC 7
refers to a very precise grade of bearings that are usable at very
high RPM in machine tool spindles. (this one seems to be good for 22k
RPM, for example). This stuff is god awful expensive, like $300 per
such bearing at McMaster.

At the same time, if you search for ABEC 7 on eBay, you will see a
huge quantity of a buck a dozen "ABEC 7" skateboard or roller skate
bearings.

I have hard times believing that they are really made to such
specs. (or that skateboards need such precision)

Are those skateboard bearings really made to ABEC 7? Or is that some
clever marketing ploy?

i