YOA01Y Gear number: 17T. Diameter: 3.17mm. External diameter: 11.35mm. Height: 10.5mm. Modulus: 0.6. Suitable for RC 1/10 buggy cars， flat cars and monster trucks. Comes with a screw for easy installation. Package Details Weight: 5.35 g Size: 2*2*1 cm Package Includes 1 × 3.17mm 17T RC Car Motor Gear 1 × Screw