Angular contact ball bearings are particularly suitable to carry conbined load, radial load as wellas thrust load in one direction. Three kinds of contact abgle: 15° , 25°, 40° are available. The greater the contact angle, the higher the axial load carring capacity of the bearing will be; and bearings with smaller contact-angles are recommended for high speed applications. They can be arranged in duplex (pairs), namely, "face-to-face" or "back-to-back", and "in tandem". Bearings in duplex arrangement are extremely useful for high speed applications where the load to be carried is too great for a single bearing, or the axial loads to be carried are in both directions and the axial clearance is to be controlled. The duplex bearings can be preloaded as required to increase the stiffness of the spindle on which these bearings are mounted.