The Nachi 5311 is a double-row angular contact ball bearing designed for demanding applications, featuring a 55 mm bore, 120 mm outer diameter, and 49.2 mm width, with a 20° contact angle for optimal axial and radial load capacity. It offers a dynamic load rating of 112,000 N and a static load rating of 86,500 N, ensuring reliable performance under heavy loads. Constructed from high-quality JIS SUJ2 steel, this open-type bearing operates at temperatures up to 120°C and supports high rotational speeds—up to 4,000 RPM with grease and 5,500 RPM with oil lubrication. Its precision ISO P0/ABEC 1 classification and robust design make it ideal for industrial machinery, pumps, and gearboxes where durability and precision are critical.