100X 20122A 20122B 20T + 12T 0.5 Modulus Plastic Double Gear Reduction Bilayer 0.5M Aperture 1.95Mm 2Mm 2A 2.05Mm 2B Tight Loose
100x 20122A 20122B 20T + 12T 0.5 Modulus Plastic Double Gear Reduction Bilayer 0.5M Aperture 1.95mm 2mm 2A 2.05mm 2B Tight Loose