This is a pinion gear used in the motor of the new Plarail mechanism (Nosekae Chassis). The hole diameter is 1.9mm, allowing it to be attached to the motor without any modification. The motor shaft is 2.0mm, so it is a press-fit, ensuring a secure attachment. However, using tools like a vise or hammer can make installation easier. Gear Information: Module: 0.5 Pitch Circle Diameter: 5mm Total Length (Width): 5mm Hole Diameter: 1.9mm Diameter: 6mm *Diameter is the length from the tip of a gear tooth to the tip of the opposite tooth. How about using it for motor replacement or gear breakage repair? Also, this gear seems to be used in Disney monorail Plarail models, so I think it can be used for repairs. To offer it at a low price, it will be shipped via regular mail. Please check my profile for details about regular mail. I also sell 12-tooth and 14-tooth gears. If you want 7 or more, you can add them for 20 yen each, so please contact me. Multiple types can be sold together. I sell many other pinion gears.