Features:_x000D_ _x000D_ Can be directly connected to the stepping motor, no external driver. _x000D_ High precision, adjustable speed, Angle can be set, and the speed can be real-time displayed. _x000D_ Speed controller is made with high quality circuit board which ensures a longer service life. _x000D_ This simple and easy-to-use DC motor speed controller has an stable performance. _x000D_ Designed with a digital display that shows the rate in percent of actual speed to maximum speed. _x000D_ _x000D_ Specification:_x000D_ Condition: 100% brand new_x000D_ Model: YF-20_x000D_ Control voltage: 7~30V_x000D_ Current: within 2A_x000D_ Stepper motor: common 42,57 two-phase four-wire five-wire six-wire stepper motor_x000D_ Speed description: real-time speed regulation: 0.1~999 RPM; (most 42,57 stepper motors have a maximum speed of about 350 RPM)_x000D_ Angle: 1~9999 degrees can be set; 360 degrees in a circle; Users can convert their own needs to run distance_x000D_ _x000D_ Package List:_x000D_ 1 * Speed Controller 1Can be directly connected to the stepping motor, no external driver. 2High precision, adjustable speed, Angle can be set, and the speed can be real-time displayed. 3Speed controller is made with high quality circuit board which ensures a longer service life. 4This simple and easy-to-use DC motor speed controller has an stable performance. 5Designed with a digital display that shows the rate in percent of actual speed to maximum speed.