The FAG B71909-C-T-P4S-UM is a high-precision angular contact ball bearing from the B719 series, manufactured by FAG (Schaeffler). It features a 45 mm bore diameter, 68 mm outer diameter, and a 12 mm width. This bearing is designed for demanding applications requiring high running accuracy and speed, such as machine tool spindles. The 'C' designation indicates a 15° contact angle, 'T' signifies a textile laminate cage for high-speed capability, 'P4S' denotes a special precision class (better than P4), and 'UM' means it is universally matched for arrangement in pairs or sets, allowing for flexible mounting options. It offers a basic dynamic load rating of 14.5 kN and a basic static load rating of 9.8 kN, with limiting speeds up to 42,000 rpm under oil-air lubrication.