Bones Swiss Ceramics are the fastest skateboard bearings you can buy. A winning combination of Bones precision ground and polished races, fiber reinforced high speed ball retainer, Cerbec® silicon nitride ceramic balls, Speed Cream™ racing formula lubricant, and a frictionless, non-contact shield. The advantages of using ceramic balls are that they are non-corrosive, lighter weight, harder & stronger than steel, have lower rolling friction, and last longer. This makes Bones Swiss Ceramic bearings accelerate faster, roll farther, and last longer than polished steel ball bearings. If you are looking for the very best, invest in Bones Swiss Ceramics. Allow 2 weeks for delivery.