Bicycle specific ceramic cartridge bearing for low friction spinning
Specification and quality matches original bearings selected by the engineers at the world's leading bike brands
Nylon retainer, CrMo races, Si3N4 Silicon Nitride (HRC 75-89) ball bearings
Tolerance ABEC-5
Rubber LLB (non contact) Seals
Multemp PS2 (Kyodo Yushi) Grease 
Manufacturer information: Learn more about M Part.