Ball bearings are used in a wide range of applications and industries due to their ability to reduce friction and support radial and axial loads. Here are some of the common requirements and uses for ball bearings:

1. High-speed applications: Ball bearings are commonly used in high-speed applications such as electric motors, turbines, and aerospace equipment. They are able to operate at high speeds with minimal friction and wear.

2. Heavy-load applications: Ball bearings are also used in heavy-load applications such as cranes, construction equipment, and mining machinery. They are able to support heavy loads while reducing friction and wear.

3. Precision applications: Ball bearings are used in precision applications such as machine tools, robotics, and medical equipment. They provide accurate and smooth rotation with minimal runout or vibration.

4. Low-friction applications: Ball bearings are used in low-friction applications such as bicycles, skateboards, and conveyor systems. They reduce friction and wear, allowing for smooth and efficient operation.

5. Harsh environments: Ball bearings are used in harsh environments such as marine, automotive, and chemical processing industries. They are made with materials such as stainless steel or ceramic to resist corrosion and withstand high temperatures and chemical exposure.

Overall, ball bearings are essential components in many industries and applications where smooth and efficient rotation is required.