Item Type: Step Motor Controller Type: YF-19 Power Supply Range: DC 8V~24V universal. Speed Range: 0.1~999 RPM Package List 1 x Step Motor Controller Please note that the new type and old type of this product will be sent randomly, and make sure you will not mind before ordering. 1Power Off Memory: Comes with power off memory function, the motor controller adds more convenience to the operation. 2Adjustable Speed: From 0.1 RPM to 999 RPM, the rotational speed is free and easy to adjust to meet your working needs. 3Various Function: The step motor driver also enables simple adjustment on angle, distance and delay, very practical. 4Safe Application: Ensuring reliable and efficient performance, the control module suits for 42 and 57 step motors. 5Easy Maintenance: Digital display makes the adjusting much easier, and the installation and maintenance are very easy.