Bearings extend the working life of rotating parts, such as a wheel on a shaft, by enabling components to move together smoothly while providing support and alignment. Rolling-element bearings consist of a series of balls or rollers that ride along the bearing raceway and reduce noise, vibration, and wear. Plain bearings are cylindrical-shaped components with tubular inner surfaces that fit around shafts to facilitate sliding, rotating, and oscillating movement. Spherical rod ends and spherical bearings provide a fixed point of contact between two components to allow rotational movement and to compensate for angular misalignment. Cam followers and track rollers are types of bearings that convert rotating motion to linear motion by making contact with and following a cam or a track. Bearing heaters temporarily expand the bore diameter of a bearing to help slide the bearing onto a shaft, reducing the risk of shaft damage. Slewing rings enable rotary motion between different components and support loads acting singly, or in combination, and in any direction.