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 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 contacting and following a cam or a track. Slewing rings enable rotary motion between different components and support loads acting singly, or in combination, and in any direction. Bearing adapters, withdrawal sleeves, and locknuts accurately locate and fasten tapered-bore bearings onto straight shafts. Bearing heaters temporarily expand the bore diameter of a bearing to help slide the bearing onto a shaft, reducing the risk of shaft damage. Bearing packers evenly compress grease into bearings to ensure proper lubrication and long service life.