Roller bearings offer a high load-carrying capacity, the main difference between a roller and a ball bearings being the contact area of the rolling element. Rolling elements have a larger linear contact area with the raceway, while balls have point contact. Usually operating at lower speeds due to the additional friction created with the larger contact area, the roller bearing is well suited for heavy, slower rotating assemblies. Metric & imperial sizes with cylindrical, spherical, tapered or needle rolling elements are available. Each type has unique benefits and should be selected depending upon application requirements.