1,Large input voltage range from 12-60VDC,suitable for different power source. 2,The knob switch can adjust the motor speed steplessly. 3,With the metal shell,it is easy to install and use and very safe while use. 4,The speed controller is made of premium material,durable and has long service life. 5,The motor controller is stable and has great performance while using. Features: Large input voltage range from 12-60VDC,suitable for different power source. The knob switch can adjust the motor speed steplessly. With the metal shell,it is easy to install and use and very safe while use. The speed controller  is made of premium material,durable and has long service life. The motor controller is stable and has great performance while using. Specification: Input Voltage:DC 12-60V Output Voltage:Linearity under load Output Current: 60A Continue Current: 40A Speed Adjustment Range:0- Control Frequency: 21KHz Speed Adjustment Mode:Knob Digital Display Positioning:0- Connection Type:Electric Wire Suitable for:DC Brush Motor Size:110 x 71 x 37mm / 4.33 x 2.8 x 1.46in Connection Method: NO Color Signal 1 Red Power and 2 Black Power - 3 Blue Motor and 4 Green Motor - Package List: 1 x Speed Controller Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Sold by-Minnanxin