With start/stop button, and can be controlled by external switches to meet customers' various control needs. Motor soft start function, the current increases slowly when starting the motor, no inrush current, effectively protect the motor and prolong the service life of the motor. Duty cycle, upper and lower duty cycle limits and operating frequency can be set to facilitate customers to operate according to their own motor operating characteristics. Digital encoder knob to adjust the motor speed, than ordinary potentiometer adjustment, higher precision and better consistency. With standard meter housing, convenient for customers to install. Hign-concerned Chemical:None Motor Type:DC Motor Features 1: 12v 24v Features 2: 5A DC Motor Controller Colour:Dark Gray Material:ABS Package Contents: 2 x motor controller Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.