Pulse Width Modulation (PWM) Controller Circuit Assembled in a small case. This is used to limit and control the power in our Transistor or Mosfet switched motors and circuits. It can be added to the Dual-Mosfet Mini Magnet Motor and is included in the Full controller for the Industrial Magnet Motor. It can also be added to the Mini and Large DualPole Motors. It does not come with the transistors or mosfets unless that option is selected above (which would then include heatsink, fan, case, etc.). There are two potentiometers which change either the pulse or width of the on-time. We provide the two tiny pots that can be mounted on the board but will assemble it with a larger pot that is externally mounted and with a knob on it which provides main speed control once the other pot is set.