Zero Ceramic bearings are the ultimate race day weapon. Oversized Grade 3 balls roll on races which are ground to a mirror finish after receiving Magnetite and then Cryogenic treatments for hardness and longevity, and slippery Silicone seals to produce minimum resistance. All measurements are in millimeters ABEC 5 precision cartridge bearing CERBEC USA Grade 3 Si3n4 Silicon Nitride balls 52100 high carbon Chromium alloy races Races receive 3 cryogenic treatments and a rust proof Magnetite finish "VV" type 2-lip non-contact Silicone labyrinth seals