Miniature bearings refer to metric series, with an outer diameter less than 9mm; Inch series, all kinds of bearings with diameter less than 9.525mm! The main materials are carbon steel, bearing steel, stainless steel, plastic, ceramic and so on. The inner diameter can be at least 0.6mm, and the general inner diameter is 1mm.
In ultra small aperture in the miniature bearing, miniature deep groove ball bearing type has the metric 68 series, 69 series, 60 series, etc., inch on a total of 6 R series, based on this, also can be divided into with ZZ steel dust cover bearing series, rubber sealing ring with RS miniature bearing series, teflon bearings seals series and flanged penal series and so on

common type： 
682 682ZZ MR52 MR52ZZ 692 692ZZ 683 683ZZ MR83 MR83ZZ 693 693ZZ 603 603ZZ 623 623ZZ MR74 MR74ZZ MR84 MR84ZZ 684 684ZZ MR104 MR104ZZ 694 694ZZ 604 604ZZ 624 624ZZ MR85 MR85ZZ MR95 MR95ZZ MR105 MR105ZZ 685 685ZZ MR115ZZ 695ZZ 605ZZ 625ZZ MR106 MR106ZZ MR126 MR126ZZ 686 686ZZ 696ZZ 606ZZ 626ZZ MR117 MR117ZZ MR137 MR137ZZ 687 687ZZ 607ZZ 627ZZ MR128 MR128ZZ MR148 MR148ZZ 688 688ZZ 698ZZ 608ZZ MR149 MR149ZZ 689 689ZZ 609ZZ 629ZZ 639ZZ