miniature deep groove ball bearing these are the most popular type of rolling bearings. Models: 604 - 609, 624 - 629, 6000 - 6020, 624 - 629, 6200 - 6220, 6300 - 6320, 685 - 689, 695 - 699, 6800 - 6810, 6900 - 6910, 1600, R, F600.F628, F688 WWW ODB BEARING COM