The gear and rack drives the manipulator, and the model is different from the normal module. The gear rack and the slide rail module are used to cooperate with the motor driven by the motor to achieve the purpose of delivery.Advantages: low cost, save cost by not adopting screw mechanism, adopt gear mechanism, drive big, load high, fast, steady.This model is transformed into step and iges general model download, please refer to!Also includes 3d original files, welcome to download!if you like,you can paypal for you to get this models or if you have any questions also you can email to me.