902AB single-layer gear porous thickening motor gear four-wheel drive transmission gear DIY gearbox gear（4pcs）

Number of single-layer teeth: 90 teeth
Module: 0.5 module
Aperture(d): 2mm
Tooth circle diameter(D1): 46mm
Gear thickness(H1): 4.1mm

Single gear, also known as spur gear
Modulus: 0.5
Gear outer diameter = (number of teeth + 2) * 0.5 (unit mm)
For example: 202A-2A means that the number of teeth is 20 teeth and the gear aperture is 2 mm. A means that it fits closely with the 2mm shaft. If it is B, it is loosely matched with the 2mm shaft.