There are several types of ROLLING BEARINGS FOR STEEL MILLS NSK designs. The standard type B design has asymmetrical rollers, which push the roller in to the center inner rib. This allows for quieter, smoother running bearings with low heat generation, which can be used in higher speed applications. Type C design is common in the industry, and is standard design for small sizes. The 213 series is a special design type, having a separate outerraceway guided ring to separate the rows of rollers. The E design is considered state of the art: the number and size of the rollers is optimized to provide maximum load capacity for a given size bearing. Machined bronze cages are the most popular used in steel mill application bearings (only a high temperature plastic cage is standard with the E type design). For some applications, a standard pressed steel cage can be used. All spherical roller bearing types would be found in steel mill applications.