Roller bearings are mechanical components that reduce friction between moving parts by using cylindrical rollers. They are designed to support heavy loads while allowing smooth rotation or linear movement. Commonly found in machinery, vehicles, and various industrial applications, roller bearings help improve efficiency and extend the lifespan of equipment. These bearings come in different types, including cylindrical, spherical, and tapered roller bearings, each suited for specific applications. The choice of roller bearing depends on factors like load capacity, speed, and alignment. Proper selection and maintenance of roller bearings are essential for optimal performance and reliability in machinery.