608 bearing ,the number 6 is represents the 6 series deep groove ball bearing, 0 is the size series, and 8 is the inner diameter of 8 mm,outer diameter is 22, 7mm is height and 8mm inner diameter. There are 7 steel balls and the diameter of the steel ball is 3.969mm. The bearing is divided into 608 bearings with metal shield cover and rubber seals cover. The metal shield cover is indicated by the model suffix zz (608zz), and the rubber cover is indicated by the model suffix DDU (608DDU). Materials can be with carbon steel, bearing steel (GCr15), stainless steel, plastic, ceramics, etc. The cages are: nylon cages, iron cages, copper cages etc. 608 bearings are widely used in motors, motors, electronic accessories, trolleys, skates and other related fields.