Deep groove ball bearings are non-separable and require little attention or maintenance in service, capable of operating at high speeds and are widely used radial bearings.
The bearings are mainly used to carry radial loads and a part of axial loads in two directions.  The ceramice ball bearings have some special functions and are much expensive.  The bearings rings are perhaps made of stainless steel or ceramic or chrome steel.  The bearings ball are made of ceramic materials.