A Needle Roller Bearing is designed for maximum load-carrying capacity with the smallest possible cross-sectional area. This bearing is ideal for use in transmissions, pumps, and a number of other agricultural and construction applications. Mechanically Retained and Caged Retained are the two basic versions of a needle roller bearing. The outer shell on both versions serves as a raceway for the rollers. The standard Caged version uses a cage to guide the rollers. The Mechanically retained version uses the drawn outer shell to hold and guide the rollers. More rollers can be used in a Mechanically retained bearing, allowing for higher load capacity. Caged retained rollers are able to provide higher speeds and better lubrication. Needle bearings are commonly found in transmissions, transfer cases, engines, and valve trains. With a small cross-sectional area and a high load capacity, a needle roller bearing may be used in compact areas.