1.This Motor PWM Speed Controller adopts with screw terminals easy Installation. 4.speed controller size:13x6x3.2cm/5.1 Inch x 2.4 Inch x 1.2 Inch (l x w x h).button switch size:4x1.8cm/1.5 Inch x 0.69Inch (h x w).potentiometer size: 23 x 20mm /0.9Inch x0.77Inch (h x w). knob size:15.5x23.5mm/0.6 Inchx1 Inch(h x w),Inner hole size:6mm. 2.Input Voltage Range: DC 6V-DC 60V.Power supply:12V 24V 36V 48V.Output Current: 0-30A(Can not input 220V and 110V household electricity). 3.LED Display Design which shows percentage rate of actual speed to maximum speed, so the data is readable through the LED display, you can get a precise data easily,but input voltage should be equal to the rated voltage of the DC motor 6-60V. 5.It is equipped with a momentary /stop switch and a speed control potentiometer and knob,you can regulator Stepless Variable through the potentiometer to provide a better and stable performance.