Galvanized thicker Smaller tolerance of roller Improving cage design Optimizing design of bearing ribs NU2304 bearing Dimension: d:20mm D:52mm T:21mm Weight:0.25kg 1.Material : Gcr15(Chrome steel)--China,(AISI)52100---American ,(Din) 100Cr6---Germany 2.Precision level:ABEC-1,ABEC-3,ABEC-5 P0/ P6 /P5/P4 3.Fields Used in : Motorcycle , Motor , Pump ,Fan,Air conditioner ,Microwave Oven,Rangehood, ...