Maxon planetary gearbox 

Gear ratio 370:1 

Maximum torque 0.375 Nm 

Diameter 16mm

Radio Spares 323-4874

Body has a 16mm diameter. 25.5mm long.

Shaft length is 9mm, 3mm diameter. 

Drive gear and instructions.

Unused stock. No packet.

I have a 16mm Maxon motor in my other items.