The 6 in the 608 bearing represents the 60 series deep groove ball bearing, 0 is the size series, and 8 is the inner diameter of 8 mm. Dimensions are 22mm of outer diameter, 7mm height. There are 7 steel balls and the diameter of the steel ball is 3.969mm. 608 bearings are used in motors, air conditioners, scooters, fidget Spinner, etc. 608 bearings are made of carbon steel, chrome steel, stainless steel, plastic, etc. 608ZZ / 608 2RS from LSKD