Bearings reduce friction by providing smooth metal balls or rollers and a smooth inner and outer metal for the balls to roll against.
These balls or rollers "bear" the load, allowing the device to smoothly.
Specifications:
MR126ZZ
Size: 6 x 12 x 4mm(Inner Diameter x Outer Diameter x Thickness)
Package Included:
10pcs x Bearings
Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.

What's in the box
10pcs x Bearings