The model suffix of import bearing with a dust cover is 2Z, there are two different designs of products. Thin steel dust cover are used for the smaller bearings,it form a narrow clearance with the inner ring shoulder surface. The larger bearings and SKF Explorer bearing have a groove in the inner side, the dust extended into the groove.Bearings with dust cover is mainly used for inner ring rotation applications. If the outer ring rotation, once when the bearing reaches a certain speed, there is the risk of oil leakage from bearing.