1. Product Overview B28-31 non-standard single-row open deep groove ball bearing, overall dimension 28mm inner bore × 60mm outer diameter × 31mm ultra-wide width, small inner hole plus extra wide heavy-duty structural design, fully interchangeable with original NSK B28-31, widely matched to multiple passenger car CVT driven pulley large torque transmission system. Open design without rubber sealing lips, equipped with stamped low-carbon steel cage and factory standard C0