When buying bearings it's best to go for ones with a decent ABEC (quality) rating, go for 5 or better. Any eBay stuff without a rating will be just plain nasty !
Meh, abec ratings make sense for stuff that goes really fast or you need mega tight tolerances on, but anything with a proper seal from a reasonable brand in the right size will be fine.
When buying bearings it's best to go for ones with a decent ABEC (quality) rating, go for 5 or better. Any eBay stuff without a rating will be just plain nasty !