The deep groove ball bearing means that the inner and outer ring has a channel, the rolling body is a ball.
It is generally divided into two types: the belt cage and the full ball. From the point of view of material quality, there are many kinds of bearings now.
The common bearings are generally of full steel in steel (GCR15) and stainless steel (440c), and so on. There are also some special industries where bearings are like all-ceramic ones.
The inner and outer rings and rolling bodies are made of structural ceramics such as silicon nitride, zirconia, etc. There are also plastic bearings, such as made in FEEK/PI，etc engineering plastics. The specific choice is mainly based on your use of the environment to decide.