[Type]: This is a 17287-2RS deep groove ball bearings, size is 17x28x7mm. [Durable Material]: Made of high-quality bearing steel, durability and resistance to deformity under heavy loads. [Black Sealed Cover]: Double-sided closed with rubber sealing washers to protect the bearings from dust or other foreign matter. [Package List]: Contains 2pcs 17287-2RS deep groove ball bearings which is corrosion resistant, easy to maintain. [Application]: This type of bearing is used in the bicycle industry, such as wheel hub, headsets maintenance, which can be used for mountain bikes, road bikes, racing bike etc. [Note]: In order to prolong the life of the bearing, do not spray water directly, otherwise the water penetration will cause premature failure of the.