1.Every product has a unique Manufacturing Part er label on the inner package that proves it has been qualified,which include Part er,Model er and inspection date information;2.If you have any questions about the item,please provide us the Manufacturing Part er for checking,your profits will be guaranteed.3.Using high-hardness steel, good toughness, impact resistance, bearing quality and motor service life are improved, very durable.4.High temperature resistance, high wear resistance, strong carrying capacity, sturdiness and durability, effectively protecting the gearbox motor body.5.The lower the speed, the greater the power, and the lower the sound; on the contrary, the higher the er of revolutions, the lower the power, the greater the noise, and the faster the running speed.Specifications:Material: MetalColor: SilverSize: 8.6x3.8cm/3.39x1.50inch(LxW)Weight: 458gPackage include:2 x Cable4 x Gear2 x Children Electric Car Motor