Couple of 28 precision, high-speed ball-bearing set. Includes ball-bearings for drivetrain, gear tensioner, and XCA clutch. Elements record 359051 XB808 Clutch Bell Ball-Bearing 5x12x4 (2) 940508 High-Speed Ball-Bearing 5x8x2.5 Rubber Sealed (2) 940510 High-Speed Ball-Bearing 5x10x4 Rubber Sealed (2) 940613 High-Speed Ball-Bearing 6x13x5 Rubber Sealed (2) 940815 High-Speed Ball-Bearing 8x14x4 Rubber Sealed (2) 941218 High-Speed Ball-Bearing 12x18x4 Rubber Sealed (2) 950510 Ball-Bearing 5x10x4 Flanged (2) 950814 Ball-Bearing 8x14x4 Flanged (2)