The four principal types of roller bearings are cylindrical, needle, spherical, and ____________________.

Roller Bearings

Bearings that use cylindrical rollers to maintain the separation between moving parts of a bearing, reducing friction and supporting radial and axial loads.

Cylindrical

Relating to the surface or shape of a cylinder, which is a solid geometric figure with straight parallel sides and a circular or oval cross section.

Spherical

Having the shape of a sphere; relating to or resembling a ball or globe.