This is a 1:56 speed reducing gearbox for a nema 14 or Nema 17 stepper motor.
You will need some different ball bearings
2x : 10x15x4 mm
1x: 5x10x4 mm
1x: 8x22x7 (608zz)
The case is about 40mm long so at least 45mm long m3 screws.
One m8 bolt with a hex head, m8 washer and a nut.
For a low torque nema 14 excenter can be press fitted whithout glue or set-screw.
I have no idea how it will wear.
The plan is to swap the heavy/bulky nema 17 + gearbox extruder mechanism on my printer and the plan is to use a much smaller nema 14 motor.The m8 bolt output should be useful i hope as hobbed or maybe to use a bigger feed wheel to grip the filament.