An upgrade option for cartridge wheel bearings that offer extremely low friction, improved power transfer, and a service life that far exceeds traditional steel bearings. FEATURES: Grade 3 Silicon Nitride balls Hardened races Reinforced polyamide cage and non-contact seals Hand built in Denmark High resistance to poor lubrication Intended for: Road, TT, Tri, Track, Cross, and MTB Coated races increase bearing service life by increasing hardness of race and reducing corrosion CeramicSpeed products with coated bearings include a 6-year warranty SPECS: Model # : K1311 Model Name : Cartridge Bearings Bearing O.D. (mm) : 24 Bearing I.D. (mm) : 15 Manufacturer Number : 61802 Material : Ceramic Thickness : 5