Roller Bearings Marterial: Gcr15 Seal material: Rubber,Ferrum Noise: Z1,Z2,Z3 Vibration: V1,V2,V3 Roller BearingsMarterial: Gcr15Seal material: Rubber,FerrumNoise: Z1,Z2 ... , 6901, 6902, 6903, 6904, 6905, 6906, 6907, 6908, 69097) Inch size series: R6, R8, EE3, EE48) Specifc designed bearings for motorcycle Double row Tapered roller bearings