608-ZZ Ball Bearing, this is a popular size of Skate bearing or any application that uses this size 8mm x 22mm x 7mm. Bearing is made of Chrome Steel, also bearings are Oil lubricated to be smooth. Item: 608-ZZ Ball Bearing Type: Deep groove ball bearing Material: Chrome Steel Lubrication: Oil Closures: 2 Shield, can\'t be removed and re-installed again Dimensions: 8mm x 22mm x 7mm/Metric ID (inner diameter)/Bore: 8mm OD (outer diameter): 22mm Width/Height/thickness: 7mm Size: 608ZZ:8 x 22 x 7 mm