Seismic Tekton Bearings. Spacers and speed rings are no longer needed. Bearings always sit perfectly!!! With these bearings, the 2011 IGSA World Downhill Championship was won! Features: - integrated spacers - black silicon nitride ceramic balls - self-cleaning by ceramic balls - nylon race - fits rollers with 8mm clearance - removable, rubberized bearing covers made of steel - pre-oiled with a special combination of oil and grease - heat-resistant and shatterproof - extremely hard, extremely light - corrosion resistant Content: 8 ball bearings with integrated spacers.