91A Hollow Cup Motor X5C/X5A/X5 Pinion 9 Teeth Aircraft Accessories RC Quadcopter Rotor Gear (4pcs)

91A gear: 9 teeth, 1A means it fits tightly with a shaft with a diameter of 1MM. The hole diameter is about 0.95 mm
0.5 means module, the module of this gear is 0.5
Calculation formula of outer diameter of gear: Outer diameter = (number of teeth 2) * 0.5

91A gear
Hole diameter: 0.95mm
Diameter: 3mm
Height: 4mm