This spherical roller bearing compensates for shaft misalignment through its two rows of barrel-shaped rollers running on a common spherical raceway in the outer ring. Main dimensions follow DIN 635-2: bore diameter 45.0 mm, outside diameter 100.0 mm, width 25.0 mm, mass 0.96 kg. The bore type is K, a tapered bore with 1:12 taper, intended for mounting on an adapter sleeve or tapered shaft seat rather than a straight shaft. Limiting speed is 9000 1/min, reference speed 4750 1/min. The JPA cage is a pressed-steel cage guiding the rollers. Radial internal clearance C3 (Group 3) is wider than normal, which accommodates the interference fit resulting from mounting on the tapered seat and the thermal expansion of the inner ring during operation. The E1 design denotes an optimized internal geometry for increased load rating within the same envelope dimensions. Relubrication is standard, meaning the bearing accepts grease replenishment through the design of the bearing without additional lubrication features. Dimensionally and constructionally equivalent designations include NSK 21309EAKE4C3, RHP 21309KJC3, SKF 21309CCK/C3, SKF 21309EK/C3, and SKF 21309EKW/C3.