8-Pack Full Ceramic High Speed Skateboard Bearings ZrO2/Si3N4608 Full ceramic Ultra Low Friction Bearings Set of 8 Bearings Set of 8 full ceramic skate bearings that work in high speed skate applications like skateboards, inline skate, rollerblades, roller hockey, and even the 8mm quad rollers, these bearings can be used inline skate, rollerblade and roller hockey. These bearings use for racing and competitions, this set has 8 bearings for skateboards, there is no steel ferrous mateial in these ball bearings.