The FAG B71921-E-T-P4S-UM is a high-precision angular contact ball bearing designed for spindle applications requiring extreme accuracy and rigidity. This single-row bearing features a 105 mm bore, 145 mm outer diameter, and 20 mm width. It belongs to the 719 series, known for its compact design. The 'E' suffix indicates an optimized internal design, 'T' signifies a textile laminate cage, and 'P4S' denotes a super-precision class, exceeding P4 (ABEC 7) standards, ensuring very low runout and high rotational accuracy. The 'UM' indicates universal matching for paired installation. This bearing is suitable for high-speed applications in machine tool spindles and other precision machinery.