Specifications:Color:Silver+BlackVoltage:12VCurrent:1.3APower Supply:DCHold Torque:28N.cmLead:8mmStroke:285mmFeatures:- 42 Linear screw stepper motor, T8 screw motor T screw, 3D printing, quality assurance.- Stepper motor, also known as pulse motor, based on the most basic principle of electromagnet, it is a free rotation of the electromagnet, the action  principle is to rely on changes in air gap to produce electromagnetic torque.- Excellent loadability. Its speed is not affected by the size of the load, unlike ordinary motor, when the load increases will appear when the speed of  the situation, the use of stepper motor speed and location are strict requirements.- Easy to control. Stepper motor is "step" as a unit of rotation, the digital features more obvious.- The whole structure is simple. The traditional mechanical speed and position control structure is more complex, difficult to adjust, the use of stepper   motor, making the whole structure becomes simple and compact. The speed motor converts the speed into a voltage and passes it to the input as a   feedback signal. The speed motor is a kind of auxiliary motor. The speed motor is installed at the end of the ordinary DC motor. The voltage   generated by the speed measuring motor is fed back to the DC power supply to achieve the purpose of controlling the DC motor speed.Package Included:1 x 42 Stepper Motor (With 300mm Screw)