These bearings have a relatively high precision, of which the level is above P4. The speed is relatively low, which is below 10rpm. The strict requirement on the starting friction torque is that there are respectively 5 points of torque on each circle of the two sides (20 points will be required in more strict requirements). Only when all the measured values are less than the required values is the bearing qualified. So, the surfaces of the bearing and of the cage should have good qualities. There is also a strict requirement on the parameters of design and manufacture. There are special full complement ball bearings without inner race, and also bearings with straight raceway on the inner or outer races. The deep groove ball bearings are used here. The operation mode is rotating at a low speed or swinging. The load is mainly radial and relatively small. The requirements on starting friction torque, working friction torque and rigidity are very strict. In the application of requiring shock resistance, angular contact ball bearings in pairs are also used, often after a pre-tightening force test and control. Our company also provides various types of supporting facilities of research, manufacture and test. We can also produce sensitive bearings used on framework of all sizes and structures, which are all above P5. All the sensitive bearings used on framework with a smallest friction torque made in China are all from our company.