World's Smallest Ball Bearings with Ultra-small Outer Diameter of 1.5 mm

World’s smallest steel ball bearing capable of being mass produced was born of MinebeaMitsumi’s passion for ultra precision. Although it is tiny, its precision and performance are comparable with other bearings. These bearings are being installed in Japan’s finest mechanical watches, and we expect their applications to expand into a variety of fields and products in the future.

Outer diameter of 1.50 mm
Inner diameter of 0.50 mm
Thickness (width) of 0.65 mm
Ball diameter of 0.25 mm x 6 balls

Stainless steel
World’s smallest ball bearings with same pressed-steel ball bearing cage structure as regular miniature ball bearings.


Capable of high-speed rotation of more than 5,000 rpm