This is a 13mm diameter ball bearing and a 4mm thickness.
The inner diameter of the bearing is 4 mm and is well suited for screw with M4 screw, the sides of the bearing are closed to prevent dust from entering, and the outer wall of the bearing has a groove about 1 mm deep.
These bearings are used in some 3D printer heads used to create pressure on plastic to push it into the printhead with a small gear.
A 1 mm slot is suitable for 1.75 mm diameter plastic.
- External diameter: 13 mm
- Inner diameter: 4mm
- Thickness: 4mm