Isotope Series Ceramic Hybrid Skateboard Bearings Kit

In theory I thought these would be awesome. But let's see why they are indeed not awesome.You take a precision made bearing steel on the outside, but with hard ceramic balls. Then, you "break them in" for 10,000 hours before they're sold. Ceramic is far harder than steel, so instead of getting brand new awesome bearings you get "used" bearings that are far from precision.I installed mine in inline skate wheels. I can literally rattle the wheels due to the slop in these bearings. And when I'm skating they rattle every time I lift up a skate. The wheels also have a decent amount of side to side travel due to the excess wear. This is a very weird feeling when skating because the wheels feel loose.To be honest I've never purchased a bearing so loose, nor have a skated any bearing so bad that I paid so much for.I put my Bont JESA Swiss Ceramics back in. They are phenomenal and very tight still. No concerns with a bearing failing when I'm skating 30mph down the road.You can also order ceramics from China that would be higher quality than these, but only $25...