PWM Fans
![PWM Fans](http://www.coolerguys.com/cdn/shop/collections/06b088daea7a26dfe41f8d3378fff839_1600x.jpg?v=1516738289)
Note: PWM Fans are not variable speed control fans on their own. An integrated circuit varies the speed and airflow of a fan using a pulse-width-modulated (PWM) voltage in response to temperature or system commands send typically by a computer motherboard. You can use them to run at full speed from an external supply if you adapt the plug. (PWM Adapter Cables)